Many people sign the back of a credit card as a matter of course. Others write the words "see ID" (identification), fail to sign their cards, or both sign card and write "see ID." There are even some cards that come with a see ID sticker that is placed on the front of the card, so that merchants will remember to ask for identification to assure you have a right to use the card.
From a purely legal standpoint, you are supposed to sign the back of a credit card. In small print above or below the card some variation of the following statement may occur “Not Valid Unless Signed.” If you do not sign it, you may be asked upon purchase to do so. Moreover, failing to sign may essentially break your contract with the credit card company, who requests when you receive your card that you sign it. Though this is seldom an enforced part of your contract, there is a slight chance a credit card company could refuse to extend credit to you if your card is left unsigned.
There are varied opinions on whether you should or shouldn’t sign the back of a credit card. Some companies now issue cards with people’s pictures on the front. This makes ID verification much easier, since you either do or don’t resemble the picture. Many people note that they are not only never asked for identification, but that merchants seldom ask to see the credit card back, to see ID, or to compare signatures on the card and any credit card slips. This depends on each merchant. In areas where credit card fraud occurs regularly, restrictions are likely to be tighter, and you may be requested to provide ID and sign the card before a merchant will let you make a purchase.
A number of people write see ID because their signature and picture on an ID card are better protection. It is true that signatures, even in permanent ink, can wear off over time, and it’s somewhat difficult to provide a good signature in the tiny space provided for one. Writing see ID also prevents a thief from having an opportunity to copy your signature. On a blank card the thief can merely sign in his or her own hand, and then use that signature in the future.
Legally though, you are asked by the credit card company to sign the back of a credit card. If you don’t, and the card is stolen, you may not be entitled to the same protection, particularly if the card is recovered and is unsigned. This new method of using picture ID on cards may be particularly helpful in resolving the problem, but not all credit card companies have adopted it.