I know this is a stupid question but when you pay w/ a card, you have to wait for a 2nd receipt to come with a line for tip and signature. Obviously this is because they have to swipe your card. When charging to a room, the first receipt has a line for room info, tip, and signature, so I assume that signing it and leaving is all that's expected. However, it occurred to me that I've never asked about the process, especially since I could just write whatever I want and I assume it would be hard to track me down if I were intent on stealing a meal. Am I supposed to wait for the waiter to come back and confirm that the charge was successful?