This is really problematic with totaled/stolen cars, but really not specific to Tesla as other brand cars have a significant amount of information in there too.

This is really problematic with totaled/stolen cars, but really not specific to Tesla as other brand cars have a significant amount of information in there too. When you sell a device, any kind of device (car but also computer, hard drive, TV, ... event flat!), you reset it or remove all your stuff. That's your responsibility. But when the car (or device) is not going out of your hands while you manage it, it's a totally different question and not a simple one. Of course on computers/phones/hard drives we have encryption now, maybe it's time for cars to have that too? linked to the finger of the driver? maybe time for something like Touch/FaceID? Otherwise it'll be fun to wander in a scrapyard in the next few years with a computer and see what you can gather... won't be for spare-parts anymore :-/