I hear about credit card fraud all the time, which I why I get a little annoyed when I make credit card purchases and they don't check my ID.
It's a good idea to keep a close eye on your credit card and check your statements. One person decided he wanted to find out how far the credit card insecurity goes. Specifically, he wanted to know whether or not a person's signature gets checked for authenticity (we have all signed that little slip that says we will abide by the cardholder agreement). He found out, and he posted his findings on the web. Call it a prank with a purpose.