Fraudulent Credit Card charges

At a restaurant, in most cases it is the staff- don't be so trustful. A couple of years ago there was a documentary explaining the fraud. In restaurants and bars, the server runs your card through a portable reader before or after swiping your card for payment. All the info from the cards are downloaded to a computer. Card blanks are easy to buy- they can either made duplicate cards or sale the info. About 4 years ago we went to dinner at one of the restaurants by the beach here in "Z" and used a card for we had just enough pesos for breakfast and taxi to the airport. We are at home about 3 days after leaving "Z"- credit card security called and wanted to know if we were both home and did we have our cards(of course we did). A card was used twice at a mini mart in Cal: purchase for gas and a purchase for food inside. Kathie was driving to Chicago 2 years ago and used the card 2 times on the trip up- 1 for gas and then 1 for food at MacDonald's. Because fraud is so prevalent, everyone needs to monitor the charges all the time.