The only places I have seen these signs are in gas stations/connivance stores, and IMO they only do it to force you to use the ATM machine that makes them cash instead of costing them cash.
To me stores who break the agreement deserve to be punished. If you don't want to follow the rules then you don't have accept credit. The stores decide what payments they will accept, but if they choose to accept a credit card they have abide by the TOS.
Also, to those saying "I wouldn't let you shop in my store." You can report a store without them ever knowing who reported them. What are you going to do ban everyone?