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AI scanner used in hundreds of US schools misses knives (bbc.co.uk)
45 points by pmoriarty on May 23, 2023 | hide | past | favorite | 55 comments


Pointy and edged things come in literally all shapes and sizes. This kind of thing can plausibly have some value, but I'm not sure it's worth the costs given how easy it is to defeat.

I carried a knife to school every day. Granted, I used it as a pry bar more than as a knife, and opened a lot of boxes with it, but somehow it wasn't a big deal. I brought one into show and tell in kindergarten. My father's generation kept guns at school to go hunting with after school.

Meanwhile, you can be killed without any tools, or with improvised weapons. Banning all weapons does not make an area safe. I'm not even sure it makes it safer - there are plenty of examples in US schools alone of kids being murdered (or nearly murdered) without any weapons at all.

The problem is much, much deeper than mere 'access to weapons', even supposing you could remove weapons entirely - which you can't - and that's even ignoring the fact that weapons are not a specific class of items. What makes something a weapon is how it is used. Cars are the most obvious point to make, here, but you could just as easily use a chair or anything else that gives you more reach, a harder hit, mechanical advantage to cause more damage, etc. Thinking you can look around a room and detect and remove all the weapons is ridiculous, humans are far too versatile for such a childish attitude to be effective. A room with no weapons in it has no people in it.


Right. People have been killing eachother since the beginning of time, no guns needed. I think it boils down to a societal ill that makes people want to kill eachother, weapons or not.


Weapons or not, but the weapon of choice still makes a difference. A rifle kills faster than a knife, for example.


I'd love an experiment to prove this out. Take a room roughly equivalent in size to an average classroom and containing chairs, desks, wall hangings etc as would be found in most classrooms. Put a target dummy at one end of the room that can measure impact forces to various parts of the dummy. Define "death" conditions for the dummy - not just raw force, we want to allow for things like a knife to the throat.

Have people attack the dummy, starting from the other end of the room. Some participants will be given weapons like guns or knives, others will have to improvise with what's in the room. Measure the time it takes and use health monitoring devices to estimate the level of physical effort the participant applied.

Without doing this experiment I'm already pretty confident that a plot of time to kill will show the group given guns far ahead of the knife group or improv group. After all, they only have to aim and pull the trigger while the other groups have to move across the room. Likewise, the gun group would show far lower physical effort than the others, from the movement across the room as well as the greater need to directly apply human-sourced force. The knife group has to swing / stab / slice with enough force to meet the death conditions. The improv group has to potentially disassemble or rip apart something to then have a sharp or blunt instrument, then they still need to apply their own force like the knife group. Naturally this might change somewhat if we go nuts with the guns, like big heavy rifles or machine guns. Those would require some substantial physical effort. But handguns or the average AR-15? Not really.

Guns are a fast, low effort way to apply potentially lethal damage to a human target. You can absolutely apply lethal damage to a human in an uncountable number of other ways, but they are almost universally slower and higher effort.

Thus, we see frequent mass killings using guns, but knife incidents with high death totals are pretty rare.


there is a german comedian with a piece about the dangers of driving under the influence of alcohol. the plot was something along the lines of:

"did you know that 20% of car accidents happen under the influence?

well that means in return that 80% of accidents happen with sober drivers!

i hence request immediate action and emergency beer stations to be established on all roads."


All the semantics in the world won't change the fact that these efforts are about mitigation, not elimination, of risk. Enough with the strawman.


About fifteen years ago one of my friends got suspended for bringing a knife in. He was going on a school trip and put his clothes in his camping backpack which always stored a small knife. The school searched the bags, looking for alcohol or something, and found the knife. The school had a zero tolerance policy, so no logic was applied.

I was really annoyed, so I cataloged all the knives already present in the school. I walked into the teachers break room (no one really noticed me): three kitchen knives on the drying rack. The wood shop had tons of sharp knife-like tools. Pointed scissors in the art room. A teacher noticed what I was doing and showed me the pen knife on their key chain. Most classrooms had a letter opener, box cutter, or similar at the teachers desk. I think I found thirty knives before I gave up.

Students need knives and sharp objects to learn. Controlling access is fine but eliminating knives if a fools errand.


So, the text of NC’s statute prohibiting knives in schools also applies to colleges, and prohibits basically any “sharp or pointed object,” with exceptions for “instructional or maintenance” purposes. Still, it could encompass everything from kitchen knives in an apartment on campus to tools in someone’s car, tools in the makerspace (which is not technically instructional), etc.

Does anyone know if this could be attacked as overly vague since it would encompass so many things that are regularly brought to and allowed on campus?


Probably could be attacked, but that could harm the children. Politically, this sounds like suicide.


What was the point of tracking all the knives and giving up because you were succeeding in your goal of finding many knives?


There wasn't a high level goal. I was a student who was frustrated that a knife in a kids backpack was a huge issue, but the dozens of knives already in school were fine.


Were you able to take this data to get your friend's "record" cleared? Hopefully there isn't any written record for these kinds of things.


No record.


Some posts are missing the point. It's not to deter criminals with rational mind and time to plan. it's to deter common scenario of crime of opportunities and/or passion.

It's not difference than lock on your door, a drug addict see your front door unlock, they'll try to steal something, but they aren't gonna figure out how to pick a lock or break a window to cause a ruckus.


Sure, but this device is significantly more expensive than a standard metal detector, and at the the end of the day not necessarily "better".

For schools in particular, it does not seem like a good use of funds to buy super expensive metal detectors when the intent is only to deter "common scenarios" instead of dedicated attackers. Or do you disagree?


Oh, agree. It's a waste of money but I went to high school with metal detectors in 90s in NYC. It was a bad optic and still is. Imagine your kids going thru metal detectors when entering school.


Why is it bad to go through metal detectors to go to school?

I go through a metal detector when I go into work.

I go through a metal detector when I enter a courthouse.

I go through a metal detector when I go into the Capitol.

None of these things detracts from the gravitas of those places, and none of them makes any of those places feel less safe.

Especially when the alternatives include impinging on fundamental rights or forcing kids to go through sometimes horrifying active shooter drills, I have a hard time understanding the objection to metal detectors.


I'd be surprised if schools with metal detectors don't have active shooter drills. Mass shooters aren't deterred by metal detectors. They show up armed and walk into the building shooting.

Metal detectors are better at preventing situations like gang violence where rivals carry every day "just in case".


> none of them makes any of those places feel less safe

Experiences certainly vary: security checkpoints definitely make me feel less safe, whether or not they include metal detectors, so I avoid going into any place which has one.

I would go to some significant effort to avoid putting my child through that experience every schoolday. What a drag on one's educational experience that would be!


i have a hard time understanding the requirement.

then again i only ever went throu a metal detector at the airport; which neither detected my pocket knife nor the screwdriver in my bag, but the guards made a real fuss about that half-filled bottle of juice.


Metal detectors in schools solve school shootings?


Security measures deter mass shooters, including school shooters, yes.

> Drake told reporters that "there was another location that was mentioned, but because of threat assessment by the suspect, too much security, they decided not to."

https://www.newsweek.com/covenant-school-shooter-audrey-hale...


Active shooter drills are very boring and met with mockery fwiw.


somethings clearly in the wrong.

saying as someone who went to a semi-private school run by nuns where pupils would get written up for running.


> Sure, but this device is significantly more expensive than a standard metal detector,

Ceramic knifes exists.


I wouldn't want to fall a victim to a nirvana fallacy, but a person who wants to get a knife into a school could throw the knife over the school fence and pick the knife later. No kind of security scanner can really help in this scenario.


The scanners are usually at the entrance to the buildings, so you'd theoretically detect it being brought into the building. There are not often scanners at the fenceline or outer perimeter, so no need to lob it over the fence.

A bigger issue for schools, IME, is all the after-hours activities where students have access to the buildings, but there are no scanners being operated. It is easy to bring things in during those times and stash weapons in lockers or other areas. Similarly, it is easier to have an accomplice open a side door to let someone in without being detected during these off hours.


For my high school we only had scanners on external exits that kids came in from the outside world. There were no scanners on doors to the outdoor fields that were inside the perimeter fence. So kids went out for football and PE and band and whatnot without passing through scanners.

And even if there were scanners it’s pretty easy to hide a knife in football equipment or a tuba or something.


Kids have four years to observe the security and to probe it in various ways. If they want to get a blade into the school, they will. I imagine that there are a large number that do it ever year for no other reason than the joy of exploiting the vulnerability.


It's crazy that such devices are installed at schools at all.

Also - metal detectors won't detect ceramic knives. So it's a security theatre anyway.


You're not really defending against competent malicious adults which plan everything in advance.

You're defending against angry teens who might decide on doing it because one day something pushed them over an emotional edge. In that case, just knowing there are security measures to overcome might be enough to make them never try in the first place. You're not defending against rational actor, you're defending against emotional actor and security theatre is effective against emotional actors.


Is there any evidence that’s actually true? Being emotional doesn’t immediately change someone into a brain dead moron especially when someone seethes for a long time before acting. Any would be attacker who knows the security even exists will necessarily plan around it from their first fantasy.

Just feels like one of those solutions only we could come up with without actually solving anything. The teen TSA after school special version except with more dead kids.


It’s not a matter of “being emotional”, but rather of emotional awareness and regulation, which people in general, and teenagers in particular, are sometimes not the best at.

There are broadly two solutions (to that, not premeditated crimes): Help people to get better at that, and/or minimize situations where actions carried out in a moment can have terrible outcomes.

Sometimes, one will be much more effective or feasible than the other; often a combination can work.


> You're not really defending against competent malicious adults which plan everything in advance.

> You're defending against angry teens who might decide on doing it because one day something pushed them over an emotional edge.

I thought these scanners were installed (at least originally) mainly because of stuff like gang violence. I'd think a gang member (in their way) would be more like a "rational actor."

Also you'd have to differentiate the "smuggling a weapon" from "stabbing." The weapon smuggling part might be rational, but the stabbing itself be emotional and irrational.


An angry teen can grab a ceramic knife from the kitchen - no need to plan anything. You can also buy them at ordinary grocery stores. I have a few of them in my kitchen as well - they are really great.


That has been one of the points I have been making about these devices when discussed in security forums. "CIA Letter Openers" are easy to buy online, and would evade detection by any sort of metal detector, no matter if it claims to use AI or not.


i heard that tapered toothbrushes make reliable self defense weapons


Or offensive weapons; the classic prison toothbrush shiv can be a perfectly effective murder weapon, and its ergonomic handle can provide all the grip and support that an offender might need.


I've read that commercial ceramic knives have metal embedded for that reason.


They very well may but shanks can be made out of anything. Keeping stabby or knife like things out of school is an impossible task.


Not all of them. Also the handle can be easily disassembled and all the metal parts can be removed.


That would be an argument in favor of the airport scanners instead of metal detectors, which I'm not sure is a good direction.

I'm also not sure how many guns are ceramic.


> I'm also not sure how many guns are ceramic.

none


That punk pulled a Glock 7 on me. You know what that is? It's a porcelain gun made in Germany. It doesn't show up on you airport X-ray machines, and it costs more than you make here in a month.


wrong.

there is at least one.

guns made entirely of plastic are also viable.


What does viable mean here? So no springs, a plastic firing pin and a plastic barrel? Then there is the metallic case required to make it do any work. I guess you could use black powder and a wooden match. Don't forget the plastic projectile.


no there are no "ceramic guns" you can buy in the US, and unless you can tell me of one that is actually manufactured (including the barrel), they don't even exist

and there is no fully plastic gun, even polymer striker-fired guns have metal components (notably, barrel, slide)

please provide links


What's the name of that type of load testing where you just run requests in the background when real users are using your site? Dark testing or something?

Don't these companies trial these things for months in parallel with other equipment while they hone the algorithms to see what failed?


Why should they bother with any sort of testing? Customers with multi-million-dollar budgets are sitting at the table and eager to buy. And "does it actually work?" is of no real interest to anybody at the table.


Duhhhh yes I keep forgetting that there are businesses that solely exist to extract money from idiots instead of actually trying to solve a problem.

(I'm not even being sarcastic, I often forget this).


I don't think you understand how money laundering works...


Was confused at the article until I saw the .co.uk TLD.


As an European, I’m kind-of surprised that the crazy right’s “solution” isn’t to arm the kids.


More cost-effective to just arm the teachers.

https://www.nytimes.com/2022/07/31/us/teachers-guns-schools....


as an european, i'm sure these plans exist.




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