the CC company will give you money but won't take it from the merchant, so the waiter is going to get away with it and the CC company will give you the tiny amount of $6 so you can shut up. IMO OP...
happened twice to me in an Applebee's, wrote an long email to the headquarters customer service and made sure to include that ******* waiter's name, got a call from the store manager then apologizing...