I had a tow truck driver refuse to accept payment of my debit card because I was giving him a hard time about the circumstances of a boot I received. He towed me. I Called the cops. It is illegal to refuse payment. DA filed charges and they ended up having to go to court and pay fines.
I also have heard of people breaking their signs and collecting them wherever they see them and egging their offices to offset wrongful profits but I would never recommend such a thing.