Bruce Schneier explains why verifying that someone has a photo ID is a completely useless security measure:
Our goal is to somehow identify the few bad guys scattered in the sea of good guys. In an ideal world, what we would want is some kind of ID that denotes intention. We’d want all terrorists to carry a card that says “evildoer” and everyone else to carry a card that said “honest person who won’t try to hijack or blow up anything.” Then, security would be easy. We would just look at people’s IDs and, if they were evildoers, we wouldn’t let them on the airplane or into the building.
This is, of course, ridiculous, so we rely on identity as a substitute. In theory, if we know who you are, and if we have enough information about you, we can somehow predict whether you’re likely to be an evildoer. This is the basis behind CAPPS-2, the government’s new airline passenger profiling system. People are divided into two categories based on various criteria: the traveler’s address, credit history and police and tax records; flight origin and destination; whether the ticket was purchased by cash, check or credit card; whether the ticket is one way or round trip; whether the traveler is alone or with a larger party; how frequently the traveler flies; and how long before departure the ticket was purchased.
(Thanks, Bruce!)