On Christmas Eve in PHX, uniformed TSA (yes, real TSA agents) were checking ID's. I was VERY surprised, but assumed that they had intelligence that there might be some kind of incident. In addition, the TSA agents were actually asking passengers questions about where they were going (seemingly casual conversation but it seemed like they were looking for specific "types" of individuals).

Apparently, sbm13 hasn't had this experience. And before sbm13 starts lecturing, most of the ID checkers are contractors. However, the TSA can and DOES choose to check ID's at times.