So now we have it... those of us traveling thousands of miles every year face the shoe carnival at security at random airports for random reasons, but the minimum wage folks who work at the airport can wander through (unless they trigger the alarm). So pack whatever plastique you want in your shoes, airport workers, and stash it at the kiosk until your confederates show up to purchase a mocha and plastique to go.

Now where is the weakest link? I don't care how much background checking you can possibly do, turnover at the fast food places and so forth in the airport is high and it strikes me that half the airports are effectively giving out IDs like Cracker Jack prizes because you cannot possibly do good background checks in that kind of environment. (A thorough set of backgrounds takes several weeks to accomplish and I cannot imagine that Mickey D's is telling new hires to wait a couple weeks before they start.) And even so, the person may pass every check because they are clean, but if they can be influenced by others and incented (by threat of force or monetary gain), they will be compliant. And for that matter, there's nothing to say that they aren't simply a "sleeper" whose sole responsibility is to gain familiarity with the airport and its security processes -- the person you see every day, is the person you relax around.

And all the stupid shoe carnivals and SSSS checks will do us no good.