"Credit card only" is a sure sign of money laundering: it's a way to game the cash vs credit ratio.
(Edit: maybe "sure sign" is a little bit hasty, but I think the other possible reasons for a "credit card only" sign are actually worse morally than money laundering)
(Edit: maybe "sure sign" is a little bit hasty, but I think the other possible reasons for a "credit card only" sign are actually worse morally than money laundering)