I know, I was just letting my conspiracy theory tinfoil hat show.
For Example: a modern vehicle can throw a check engine light for anything, a friend of mine had to take their vehicle in to the dealer so that they could update the firmware in the ECU. All the dealership did was plug in a computer and hit a few buttons. Sure, it was "free" because it was under warranty, but would they have done it for free on a vehicle just outside it's warranty? Hell no. He HAD to take it to the dealer, because only they had the special tool to fix it. He also HAD to take it in because it would have voided his warranty to take it elsewhere. Also, he loses his warranty if he doesn't bring it in at the mileage intervals to replace certain parts whether they're worn out or not. Do they cover these wear items under the warranty? Hell no, but if you don't replace them when they tell you, you'll lose your warranty. Also, there was nothing horribly wrong with the car, it just had a check engine light. It didn't affect power or gas mileage, but say he needs to renew his registration, he needs the check engine light off to pass inspection, to get the CEL off, he's gotta take it to the dealer. If he doesn't pay the dealer to fix it, the government won't let him drive his car on the street.
The system is rigged to fuck you over.