Originally Posted by
cestmoi123
The vendor issue aside, this sort of random response is exactly the right way to do it. Screening is all about raising the risk for someone who actually wants to do harm, which minimizing the negative impact on the vast vast vast majority of people who don't.
So, if we go back to 9/10/01 screening (metal detector, shoes on, as many liquids as you want, etc.), but randomly assign people to an extra layer (NoS or patdown) of screening, it raises the risk profile to someone who wants to smuggle something through (since they won't know for sure if they have to prepare for WTMD or NoS) while reducing the overall burden dramatically.
The problem is that 9/11 involved many people. So what if random screening stopped one or two of them? The rest still made it through, and presumably the ones caught wouldn't have spilled the beans right away, either.
I know the principle says that randomness adds an extra element, but it's one which IMHO is fairly easily defeated as well.