Can I see some ID?

Or, Security and Privacy are Complimentary, Part MCVII:

Later, I met one executive who told me that at the same time of my incident at another restaurant owned by the corporation, a server was using stolen credit card numbers by wearing a small camera on him. He would always check ID’s and would quickly flash the ID and credit card in front of the camera. That way, he could sell the credit card number and address of someone who had no reason to report their card as stolen. Presumably they could then use it on the internet as many sites require the billing address when using a credit card. The corporation decided that there was too much liability in a restaurant employee having access to someone’s drivers license and began specifically requesting servers to not do so except to verify that the person was of legal drinking age. (“How I Learned To Start Worrying And Hate Showing My ID“, Consumerist)

I hadn’t thought about this particular aspect of stealing credit cards. It seems pretty helpful to have address and date of birth. When I think about this, the chaotic nature of how those around us accumulate and use information is hard to predict or track. There’s a value of minimal disclosure here. It’s yet another example of how protecting privacy protects security as well. Asking people to be aware of what emerges from the chaotic swirl of information is expensive.

Historically, the card brands have demanded that their cards be honored based only on the card system. They used to back you if a store asked for ID. As the system has come under attack, they’ve backed away from that, but the current state is hard to discern.

Consistency is an important part of how people form mental models. The whole world is making different demands about what’s secret (is your address a security string? Your frequent flyer number? The first street you lived on?) The demands banks and merchants are changing rapidly from a consumer perspective. (Quick, do you know what the CARD act changes?) When the rules for consumers are chaotic, what emerges is misconceptions, superstition and best practices.

In the world of security, we’re going to have to work hard to provide a comprehensible set of workable and effective advice for people to follow.