One is owned by the government. Another is owned by a private company that extorts motorists. These fines never reach the DMV unless you refuse to pay.
They are usually on the roadside in large metal boxes as opposed to being mounted on above the light signals.
Accidents happen all the time. Work trucks hit pot holes and paint splashes onto those cameras blocking the lens and flash.
Debris falls of trees knocking the cameras down.
Tea falls out of ships on rough seas in Boston Harbor. All kinds of accidents can happen.
Be safe out there.
In my state, camera tickets don't mean shit, throw them in the trash, and they only mean something if they ever send someone to your door and you answer it.