Well, somebody needs to play Devil's Advocate here, so I will. What if onboard vehicle computers truthfully are (or soon will become) so complicated - and so integral to the functioning of the vehicle - that an untrained hobbyist screwing with it could cause injury or death?
Fuck, man, brakes have been like that for a hundred goddamn years!
Stop letting "buh-buh-buh-computers!" be an excuse for corporate sociopaths and nanny-state asswipes to destroy your rights. Seriously.
We have two choices: we can be free, or we can be safe. These are mutually exclusive. And in the United States of America, the only correct choice is to be free. Sniveling infantile cowards who think otherwise can fuck off and die.