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Old Oct 1, 16, 6:55 pm
Join Date: Sep 2001
Location: Arizona, USA
Posts: 2,298
A TSA staff member once explained to me that the percentage of random alarms is variable. I do not know if it changes by shift, airport, checkpoint, or all of the above.

The sensitivity of the metal detector is also variable. It is my understanding that the designated PreCheck detectors are set at a much lower sensitivity. I started to take out my large set of keys, including an electronic transmitter. The agent said, "believe me; you can leave those in your pocket." She was right.

The problem arises when a single metal detector serves multiple purposes. The same outfit, accessories, etc. will alarm at one checkpoint but not at another based on the designation of that particular machine.

I've experienced random quite a few times. It used to just be the hand swab, then it was the full body scanner, then back to the hand swab. As usual: they're "consistently inconsistent."

I know that the TSA relies on a lack of predictability, but I fail to see how any of these techniques prevent an act of terrorism. The TSA's answer, of course, would be that this is SSI. That means, "we don't know; we have no data."
Mats is offline