I hope terrorists never learn how to use their pants as a weapon, because I like wearing pants on airplanes.
Seriously though, TSA blindly makes rules with absolutely no regard to the probability of something occurring.
In all walks in life as a society you have to accept some level of risk to keep things working feasibly. Now, I'm going to get all nerdy here and relate to my RL thangs but, in building design, there is always a small chance that an individual structural component will fail or the entire structure will fail. The probabilities of such events occurring are very small if designed correctly, and are usually in the magnitude of failure = .0001 but there is always a chance. You could over design every building so the probability of failure is in the realm of .00000000000001 but it's just not economically feasible. In fact it would be too damn expensive to build anything. The key is balancing risk with economy. Same goes for this crap. They are trying to take the chance of any sort of terrorist act down to one in a trillion when in doing so, are making the entire process completely ridiculous.