[ng7j5d9]

That might be a good 90% solution - car registrations are public records, which tons of companies harvest, which is why you get those annoying extended warranty junk mailers, etc.

Not all cars get registered though - some are chopped for parts (in which case that infotainment system might live on in another car), some are shipped internationally to be re-sold elsewhere, etc.

And there could be a lot of lag - some cars languish on dealer lots, get auctioned, languish on another lot, get auctioned again, etc. Or a dealer might like your car and slap dealer tags on it and keep it essentially as his personal vehicle for a while without registering it.

Lots of little opportunities for data to leak or remote functionality to be abused. There ought to be a complete, no-joke, absolutely reset everything in the car (and expire any remote access tokens) option in the car itself, that either a buyer or seller can easily invoke.