It's generally easier (in my opinion) to empty your pockets at the PreCheck line. 95% of the time you're fine, but every once in a while you'll get the single random beep going through the WTMD. In my experience I've seen three reactions to that:
1) Hold out your hands, they swab them with the wand and put the swab in the bomb sniffing machine (pockets being full is fine)
2) Manual pat down (have to empty your pockets anyways)
3) Reverse through WTMD and go through AIT (if anything is in pockets, it alerts, manual pat down and empty pockets).
YMMV.
Originally Posted by
catocony
People don't take eyeglasses off when going through metal detectors, right? Always keep in mind that the senstivity is set so that a small amount of metal is not going to alarm. RFID chips and the like won't, nor will eyeglasses, earrings and most simple jewelry.
It depends on the airport. I had a particular belt and shoes with small amount of metal in them (miniscule amounts for the shoes, to reinforce the holes for the shoelaces, not even visible from the exterior) and there was one WTMD that without fail would alarm if I was wearing one or both of them: The WTMD in IAH Terminal A. I took off my shoes and belt and people tried to "help" me by explaining I didn't need to do it, but having gone through that detector for months I knew there was no way to walk through it without setting it off.