Whenever I see/hear the term "random search", my first thought is, "how pointless".

If they're doing one out of ten, and aren't looking for something in particular (big bag, foreign-looking, etc), the odds are excellent that they would MISS any terrorist in the group.

Besides, they wouldn't actually have to do it themselves. All they would need to do is what some drug transporters do: give the "package" to some unsuspecting fool who's willing to take $10 to carry something on board because the terrorist is "overloaded". Just hand the backpack to Mr./Ms. CleanCut Helpful and get it past the inspection point.

Sue