The insanity of ID checks
At the airport, you’re asked to show a government-issued ID along with your boarding pass before going through a security screening checkpoint.
You can elect not to show an ID, but you’re required to submit to a more rigorous (read: fairly invasive) search if you do.
There’s a few basic problems with this approach.
First is the implied increase in security that you get from a simple ID check. It’s easy to “pass” the ID check that’s performed in the security line. A real-looking ID is easy to get: ask any underage college student. Altering the information on an all ready issued ID is no walk in the park, but it is certainly feasible. With an inside contact, getting a new, valid ID issued with the desired information is easy.
In addition, only the photo is matched to the holder of the ID: it’s possible to print a fake boarding pass (Googling this is left as an exercise for the reader) to match the given ID’s information, then use a different (read: valid) boarding pass at the gate of the aircraft.
The second core problem is evident with the “multiple paths” way of looking at the ID check. A malicious person will always take the lower detection or lower risk of capture route through a security barrier or checkpoint. Falsifying an ID is much easier than trying to sneak explosives, sharp objects, or ballistics through a more thorough security screening. Therefore, the only people who do subject themselves to the no-ID, extra screening method through the security checkpoint are all, in a statistical sense, harmless travelers. This quite obviously defeats the purpose of additional screening.