Anxious to fly?

In the news today, a security scanner that can measure levels of anxiety was talked about. The article can be found at http://www.foxnews.com/story/0,2933,425722,00.html. This scanner is in the beginning stages and still has a few more years until it will actually do its job of detecting terrorists, or perhaps it will be decided then that it will not work effectively at all. For now, scientists are studying ways of reading the levels of anxiety of a person as they walk through the scanner by measuring their body temperature, their heart rate, perspiration, etc. All in all, the goal of their research now is to be able to measure different levels of anxiety, so those who are just anxious about flying are not receiving the same reading as those who have other plans.

Although I do believe it is a good idea to invent a scanner for this purpose, so we are not only relying on reading a person's facial expression, I do not think it will be possible to separate those with anxiety about flying from those who are actually terrorists. The argument can be made for either position, I feel, but in this case I would have to side with the argument that this technology probably will not work. I think that if people knew they were walking through a machine that would scan physiological aspects of themselves, like breathing rate and heart rate, that they would be anxious not only about flying or missing a flight, but also about entering the scanner itself. Wouldn't most people's breathing rate and heart rate rise if they knew they were being evaluated in such a way? I think that this level of anxiety in addition to the anxiety some people already feel about being in airports and airplanes would just make the level reading skyrocket. I don't know enough about physiology or technology to state my argument with 100% clarity, but I raise the question: wouldn't high levels of anxiety appear on the screen the same as a terrorist's levels of anxiety? After all, aren't they terrorists trained to be calm in such situations?