I had always heard about them lowering your temperature if you had a fever - I never considered that they could lower a normal body temp too. I just never thought about it before. Given this reality, maybe the "screeners" should start DQ-ing people who line up with temps lower than normal also.
They do it if you have a fever first. Then you take a few of these, give them a couple hours, and you may end up with a temperature lower than normal. Happened to me nearly every time I had a fever and took aspirin. You feel weak, but much healthier (though that is a false feeling.)