Points galore basically has it right about the other thread. The dealership and VISA haave a contract and the dealer has promised to accept VISA in payment. It is not an optional thing. If you insist, they have to accept your card. As Efrem correctly states, you don't have to insist and they may offer you something as good or better. But if you are refused and want to press it, a call to VISA support will do the trick.