It won’t be long until someone finds a way to flash the firmware or install a bootleg sensor or something else. You can already get a lot “chipped” on VAG and BMW cars.
Chances are most manufacturers are going to use a cheap USB camera. Can a raspberry pi emulate webcam? Just place the same video of you diligently staring out of the window on repeat.
As a rule, I do my own maintenance or take the car to an independent mechanic. I wouldn't trust a dealer given how misaligned their incentives are with my interests.
Don't know if that's detectable or if there's some other gotcha like filing insurance claims after a crash. I'm not in the EU, my cars are pre-modem, and seems like everyone else is guessing too. Is there anyone here who actually disables the modem in the EU and isn't a mechanic?
2) Unplug the camera or put a piece of blackout tape over the lens.
3) Enjoy!