Here is a video link on RFID (Radio Frequency Identification) credit cards.
RFID CC's
Several years ago when I was still in the working force, I was asked to give a presentation on Identity Theft. It went over so well, that I gave the same presentation several times. One of the items that is still used today, along with many others, is the "hotel electronic key." It is still being used by perpetrators to steal your identity and charge things using your CC number.
For over a year now I have the "Foil slip cover" for my credit cards. But more so, if I receive a WiFi CC, I put the little chip on my bench vise and smash it with a hammer. The card can still be used with the "swipe" method, but not RFID.
Happy trails.