But couldn't it be argued that the use of body-scanners functions as a form of strong deterrent for potential plots? If a potential terrorist understands that they will eventually be caught or that the stakes to beat the system are too high, they will look at alternative forms of terrorism simply because the investment to beat airport security is too high.
And to sort of extend my point. We always laugh at CEOs/CTOs when they fail to provision money/resources for security software and security measures in organizations. That, instead of paying for security up-front, they wait until after a disaster to respond with security measures. In this case, by criticizing the spending of scanners as a deterrent to potential plots, are we not playing the part of CEO who complains…
Similarly, the nude scanners would have done very little to stop the 9/11 hijackers, whose weapons were simple and equivalent weapons could be improvised from items that anyone can find on the other side of a checkpoint. Whatever we were doing in August 2001 to stop less-determined attacks was working back then and would work equally well today. The simplest conclusion is that whatever else is being done to stop a 9/11-style attack is working, and that the checkpoints are just a distraction.
Not that we should be surprised by that. The TSA was going to allow people to carry small knives through the checkpoints, and noted that you are already allowed to carry far more dangerous items through -- except for box cutters, because of their appearance. Then there was an outcry from people who are terrified of knives being on airplanes, and so the policy change never happened. With that kind of logic, it is a stretch to say that the checkpoints are keeping us safe.