I'm pretty sure safety deposit rooms don't have cameras for privacy reasons. Seeing as some people keep private possibly illegal things (have a friend who claims their safety deposit vault reeks of weed) or otherwise secret for other reasons. And then usually the only person who can open the actual box is the keyholder, they have to drill old boxes that get abandoned but again this is second hand info so might not me true. And they are also left alone in the room when even if they come in at a normal time of day, seeing as the other boxes shouldn't both be locked shut and connected to a wall theft is usually either not a problem or obvious enough to stop them before they get out of the vault. But this is also for safety deposit boxes, I don't know how they store diamonds in a diamond vault. So basically none of this info is relevant except that they would be left alone with no camera for privacy reasons.