[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.