This may be stupid, but we have a large trucking business in our community. One of the truckers wanted to open an account and use the address of the company as the mailing address. He is basically homeless because he lives out of his truck. We said no to the account because he does not actually live at the trucking company and he has no other street address. Was this correct thinking on our part?

Did you do this because of your bank's policy? CIP only requires a street address, which I believe can be residential or business.

I agree. You only have to obtain a verifiable physical address. My bank's CIP specifically allows us to use a relative's or employer's address if the applicant has no permanent physcial address. You'll need to review (and perhaps revise) your bank's CIP.