"I have recommended that any customer that uses the ND more then five times in a three month period an agreement should be obtained"
Why, what additional risk is presented by the customer that does it more than five times versus the customer that only does five. Heck, if that was the case, I would have to sign one with my bank as I never go into the lobby and make most of my deposits at night or on the weekends.
Many banks have a standard night depository agreement built into their depositor's agreement and it is not a stand alone document. Standalone documents are usually used when a business customer wants to deposit bags into the night depository and retrieve them the next day or some other similar type of service.
The opinions expressed here should not be construed to be those of my employer: PPDocs.com