What if Reid had hidden the explosives in his underwear, or inside a bodily orifice? Where do we stop in our quest to be 100% safe? I think we have to face the fact that we're never going to be 100% safe and that we need to draw the line on invasion of privacy at some reasonable place. We're putting nearly all of our efforts into air passengers. As others have pointed out, there are plenty of other vulnerabilities in our society.