You dine at a fine restauraunt or perhaps a greasy spoon and you hand the waiter or waitress your credit card. The server comes back and you leave the spot designated for leaving tips BLANK because the service was no good. Later, unbeknownst to you, the server includes a nice big juicy tip for him or herself and you are charged for her malfeasance that you did not intend. What are your legal options ?
If the server had altered a check or other note of commercial paper then there are laws that effect the legitiamacy of such a note. A universal defense of commercial paper may be that there is a forgery involved or a fraud in the execution. The material alteration of a note is a complete defense against a holder, and a partial defense against a holder in due course. A party that claims to be a "Holder in Due Course" may make claim that you have an obligation to make good on a check that you did not in actuality authorize. Varying jurisdictions, have varying statute of limitations for a Holder In Due Course to sue the check’s maker for its face value. But the question remains, is a receipt at a greasy spoon commercial paper ?
The Uniform Commercial Code that in part regulates unsecured promissory notes does not regulate these types of disputes. In the fast modern age it may seem an interesting intellectual exercise to imagine how the regulated commercial paper market would treat these types of disputes as both a check and a restuaruant receipts seem to be "Promises To Pay". Nevertheless, a resturaunt receipt is not a negotiable instrument. A negotiable instrument is a document guaranteeing the payment of a specific amount of money, either on demand, or at a time established by the payer and set down in writing in name on the negotiable instrument. A negotiable instrument is a type of contract that promises to pay and warrants payment without condition. A restauraunt receipt as such is not a negotiable instrument. Call your credit card company and see if you can get the charge removed.