Though they don’t get all the blame; if you manage to fly from New York to Los Angeles without a valid boarding pass, it takes incompetence at far more than just one level.
Not only did the man in question (a Nigerian) not have a valid passport, but he was using someone else’s EXPIRED boarding pass.
Not to worry, though. This just proves that the system works.
I’m sure the TSA will assure us that all proper procedures were followed.