Small towns making deals with companies to go cashless need merely to look at a federal note, knows as dollar bills to us, and they will see that “this note is legal tender for all debts public and private” this extends to lesser denominations know to us as coins. When parking we assume a debt satisfied by inserting coins into the meter. Remember we are trying to pay the debt, but if a person doesn’t have a phone, they can’t park if coin is not accepted. For towns to arbitrarily make such a decision will most certainly be challenged. Remember, legal tender is being offered but not accepted.