If you don't like remote access to your Tesla, then go into the settings, locate the "Remote Access" slider, and slide it from ON to OFF.
If you don't want updates being applied to your car, don't press the INSTALL NOW button when the prompt appears, nor the SET FOR THIS TIME option to install it later.
Where did you get this idea that remote access can't be disabled and that updates happen without user intervention?
Tesla cars connect to the net via a standard SIM card arrangement. So there is a SIM card somewhere inside the dash that you could find and pop out if you really wanted to be sure. But then its goodbye autopilot, etc.
Autopilot will still work fine. It may receive periodic data updates, but it doesn't require a connection to operate. All you'd lose would be remote access through the app, further software updates, and any remote diagnostics Tesla might be able to do if you have a problem, assuming you also kept the car off WiFi.
That to me seems like the best option, considering a Tesla owner could then put the car back in when they need more assistance with the car or just, as you said, connect it to WiFi.
That seems like an agreeable compromise in my book, it requires user connect for Tesla access.
I don't know how one really could check that. At some point you have to trust the manufacturer to do what they say they do. Or don't, but in that case you can't really buy any car, since even if they don't advertise remote access, they could be lying.
I don't think I'll ever trust the manufacturer. I always need to check for myself. There is a lot of cool stuff I have learned over the years about cars as a result.
That's a lot easier than tearing apart every piece of software in a car to look for security vulnerabilities, intentional backdoors, and private information leaks.
I'm doing OK so far just buying older cars that were never saddled with any such crap, but I imagine that when enough time has gone by that I seriously have to consider a vehicle built that comes ready-to-exploit from the factory, enough hobbyists will have figured out how it's done that ripping out the radio won't be such a challenge.
If you don't want updates being applied to your car, don't press the INSTALL NOW button when the prompt appears, nor the SET FOR THIS TIME option to install it later.
Where did you get this idea that remote access can't be disabled and that updates happen without user intervention?