see... on VISA's own page it says the following:
Request a signature. Ask the cardholder to sign the card and provide current government identification, such as a driver's license or passport (if local law permits).
I know some states have the following laws (this is from Indiana):
Credit-Card Signature: Usually all the ID Needed
"When you pay for merchandise with a Visa card, MasterCard, or
American Express any store that accepts these cards should accept
yours too, no questions asked. It's part of the deal that merchants
agree to when they become participating members. They must check your signature and the card - electronically or by telephone - to be sure
it's valid. Once the answer comes up yes, they can to ahead and
charge. They can't ask you for any further identification - not a
license plate number, Social Security number, proof of address, phone number, or picture ID."
Canada of course may be different... but why risk losing your ability to take credit cards?