The trouble is that stores are not supposed to accept credit cards that have not been signed by the customer. It's a part of the agreement with the credit card companies.

If you don't sign the back of your credit card, you can occasionally run into a store clerk who will make a fuss about it. This can lead to the rather humorous story of clerks insisting you sign it, then they accept the card from you without a fuss.

But if you think about it, this also means you aren't protecting your card in the event of a theft. The thief's signature could easily be accepted as your own. Many clerks will not bother to check ID even in that circumstance.

But this does lead me to my own favorite way of protecting a credit card. I simply write "SEE ID" on the back, along with my signature. Those rare times that a clerk actually checks the card for a signature, there is an increased chance they will ask for an ID. Not a great one still; probably less than half of the clerks that look at the back of my card actually ask for an ID.

A few stores ask for ID as a matter of course. I worked for one such company while I was in college. The excuses for not having an ID were always quite interesting. Most were apparently kept in cars, although people showed a strong tendency to get lost on the way back to the store.

But then there was the case of the man who claimed to be shopping with his wife's card. No, the woman he was shopping with was not his wife. Yes, upon calling in the card after the rejection, the card was stolen.

Frankly, signing or not signing your card does very little to protect it from abuse. There are too many places where neither the signature nor the identification of the card user (or abuser) will be checked. The best things you can do to protect your card is to be careful about it and report thefts quickly. But I do like having the "See ID" request on my cards to make things just a little harder for a thief at those rare places that do check.