Whenever possible, don't let your credit cards out of your sight. Stories abound of service professionals taking a card to process it and helping themselves to the data via a handheld skimmer in the process. "Waiters and waitresses can have skimmers, and all they have to do is run it through and they have your information," says Cunningham.

In reality, keeping your card in view might not always be practical, although some establishments might give you the option of bringing your card up to the front to pay your bill. If you're in a store or market, though, you should be able to observe the transaction. If you're really concerned, plan to pay for meals in cash. Levin says there's nothing wrong with letting your instinct guide you. If something seems fishy, go elsewhere.