How 'bout some pulse shaping. Rising edge of the camera power triggers a latch, whose output is pulse-shaped so that you get a little attention-catching "LED fl

How 'bout some pulse shaping. Rising edge of the camera power triggers a latch, whose output is pulse-shaped so that you get a little attention-catching "LED flash" when the camera turns on (brightness tapers off quickly) and is just dimly / visibly lit beyond that. This could be done with 1970s hardware with maybe two chips and some passives. Maybe one chip if you're getting ingenious.