Who here did not think of Bruce Schneier after reading in the lead paragraph: "...that’s the conclusion of Charles C. Mann, who put the T.S.A. to the test with the help of one of America’s top security experts"?
I also don't think the people in charge at the TSA are so stupid as to not have considered that someone might alter a boarding pass.
I'm reminded of a post here a few weeks ago, I don't recall the subject exactly but I believe it quoted Henry Kissinger, who said until you are on the "inside" of these agencies, you have no idea of the things they know, and that many things that don't make any sense from an external viewpoint DO make sense once you have all the information.