Originally Posted by gooselee

I feel like I once learned that WTMDs scan in vertical zones. If I'm wearing a heavy watch, I will walk through the metal detector with that wrist across my chest (basically looks like I'm scratching my opposite shoulder as I'm walking through). This raises the metal in my watch up and away from my lower body where my wallet and belt are.

In my very unscientific testing when I learned about this - I used the ATL PreCheck checkpoint three times in the course of a week. Literally the same line and WTMD each time. Same shoes, belt, watch, wallet. Similar clothing (jeans and a polo shirt). WTMD alarmed the first time when I walked through normally and I had to dump my watch into my bin (which thankfully was still on the conveyor thing). Did not alarm the next two times when I raised my watch hand up.