I mention this today because a friend of mine just told me that they had accidently flown out of LaGuardia Airport a few days ago with a Leatherman in their bag, and hadn't realized it until someone caught it when they tried to board their flight back to New York today. I hear stories like this all the time, and there are even some known incidents of people accidently bringing firearms onto aircraft without anyone stopping them. (I suspect those might happen routinely but for the fact that there are very few people who forget that they are carrying a gun and then try to board an airplane.)
I suppose it shouldn't be surprising that the TSA doesn't even do the wrong job very well. It seems like a fine example of what happens when people demand that the government "do something" about a problem, without contemplating too seriously what the right "something" might be.