It takes exactly 1 "bare shelves" post on social media to kick off panic buying which cascades.
In fact it doesn't take much of a change in regular buying habits to cause that it it's all aligned in the same direction.
i.e. a chunk of the toilet paper "shortage" can just be every customer suddenly buying one more pack that day "just to be on the safe side". Your local supermarket isn't expecting that, so the shelves still clear out that day - then the last person snaps a pic for social media....
Yeah, my Great Aunt and her friends would coordinate their purchase of sugar for making preserves each year w/ the local grocer --- while each of them could have bought all they needed at once, his stocking couldn't accommodate that, so everyone would let him know when they would start, and stop, buying a 5 lb. bag each week for each year's preserves.
It's that one person on the highway driving just a little too fast and a little too close to the person in front of them, then they tap on their brakes and it starts the chain reaction of 3 hours of bumper to bumper rush hour traffic.
In fact it doesn't take much of a change in regular buying habits to cause that it it's all aligned in the same direction.
i.e. a chunk of the toilet paper "shortage" can just be every customer suddenly buying one more pack that day "just to be on the safe side". Your local supermarket isn't expecting that, so the shelves still clear out that day - then the last person snaps a pic for social media....