Per the merchant agreements with the credit card (and debit card issuers), merchants are not allowed to check id during a transaction as long as a properly signed card is presented. The only exception is if a credit card is not signed. Then they can ask for id and make you sign the card before they will accept it.

Writing "SEE ID" instead of signing the card is also a violation of the card member agreement, although in practice I don't think anyone has ever gotten in trouble for doing it.

It's really messed up the way it works, because it is usually the merchant who eventually ends up eating the cost of what ever fraud occurs. The consumer files a dispute and if the bank agrees they claw the money back from the merchant. The agreements are stacked so the merchants don't even have a good way to help prevent the fraud.

A lot of this is why I know longer use a debit card. If fraud occurs, I'm not out any money, I'll just have a pending balance sitting on a credit card for a while. It's a little bit more of a hassle, but it's probably worth it to help insulate my bank account from any thieves.