I put Check ID on my card. Signing the back of your credit card is stupid. It's like writing your PIN number on the back of your ATM card. If someone steals your card they have your signature right there to copy. I have never understood why anyone would sign the back of a credit card.
I was at a PO once and the guy ahead of me had that written on the back of his card AND THEY REFUSED TO ACCEPT THE CARD BECAUSE THEY COULDN'T MATCH THE SIGNATURE.