A check card is most often called a debit card. I use mine at the grocery store. It's actually my ATM card that is also a check card. There have been horror stories of restaurant workers taking your credit card to the cashier and while they have it, they'll take down the number and use it later. This has happened in gas stations, too, and many other places. I heard of a person having their card number stolen in a store by another customer who standing too closely, who had a photographic memory and simply memorized it. Your number can be stolen anywhere it's been used. Also, be sure to shred any old bill stubs that have your card numbers on them, or any correspondence from credit card companies that includes your card numbers. People have been known to go through the garbage to find old bills and use the numbers. There are so many ways for people to get your credit card information. Melanie