[bronzeage]

It's also a problem that the camera could have degraded vision that's inadequate for self driving yet report no problem at all and continue driving as if everything's fine.

I'm pretty sure your situation isn't the only way the vision can be obstructed, maybe liquids, or even bird poop can also degrade vision.

[bscphil]

This is what I would expect as well. Some kind of visual self-test, and if/when it fails, the driver gets an obvious warning and autopilot does not engage - you get some kind of clearly visible warning so that you can contact Tesla to investigate / repair the obstruction.

[servercobra]

This does happen, but maybe not in all cases. I've had it happen where lane change is no longer supported (and you get a notification) because the sun is blinding one of the pillar cameras.