I need help understanding security cameras in the vault. Our cash vault is in the same vault as our customer safe deposit boxes. What are the rules around having a camera in this vault when customers come in?

There may be particular oddities in state and local law, but generally, cameras are allowed in areas where the is no reasonable expectation of customer privacy. The vault, being your central storage point for bank owned currency, qualifies as such an area.

If a customer is concerned about the camera viewing the contents of their safe deposit box, then they should keep their box closed until they get into the privacy booth.