You've made a huge assumption here. Just because you didn't experience a false positive - doesn't mean the machine is working. There is quite a bit of evidence that it gives far too many false negatives as well.

(Such as letting thru guns in 5 checkpoints in DFW... among much other evidence.)

For that reason alone, you should consider opting-out, as a show of support for screening methods, such as a WTMD, that have a good chance of actually working.