Comment Flash Slave (Score 1) 478
get a flash slave, which is used to trigger big studio flash using a flash on the camera, basically it's a relay that will complete the circuit when it detects flash being fired, you could wire this to the interior light to produce bright lights when somebody tries to take a photo with a flash, which should overexposes
Unfortunately, it doesn't help if the person taking a picture doesn't use flash, and good cameras can compensate or adjust overexposure
Expensive systems on yacht uses infra-red camera to look for camera's ccd and fire lasers at the camera
You could try to blast the whole area with IR with spinning IR laser like a discoball