Not to deviate from my post but you must understand this. The Consumerist is one of my favorite web sites.
If you are one of those people who refuses to sign your credit card, be aware that it is invalid and merchants can and will refuse to accept it.
Unless your name is "Check ID," that's not a valid signature. End of story.
Unsigned Credit Cards Are Not Valid And Merchants Can And Will Refuse To Accept Them - The Consumerist