Mary-" the WalMarts up here in my area all have signs out front that clearly state "no soliciting".
All the Walmarts in the VA & MD area also have "no soliciting, or handing out any printed information" signs at the entrances. It must be different in other states.
My ex wife (pioneer, and probably still is) used to try to place litter-ature while I ran into the walmart to pick up a few things. On my in the store I would find the manager and tell him someone is in the parking lot bothering customers trying to sell them religous magizines. By the time I got back out, she would be sitting in the car pissed. She never figured out how the managers found out so fast that she was out there pedeling her trash and put a stop to it.