I'm just waiting to see what kinds of invasive practices we're regularly subject[0] to when an attacker decides to pack their anal cavity with explosives and have a short copper or other non-ferric lead to the blasting charge hanging out their butt. Near as I can tell, such a tactic wouldn't show up on any body scanner or metal detector and the actual detonation device could be your standard battery. After all it only took one shoe bomber to make everyone everywhere have to take off their shoes before flying.
Up until now, we have not been able to have a rational discussion of cost we as a society are paying to reduce the risk of terrorism because all logic goes out the window when the words "terrorism" or "terrorist" are used. I would imagine that the likely threat of an uncomfortable anal probing would at least prompt even the most die hard supporters of all this security theatre to question if what we are doing makes any sense at all.