Originally Posted by LtKernelPanic

Just a data point for anyone curious. Arrived at the A checkpoint at around 11:50 pm and to my total shock they had a pre-check check line open! Of course I forgot to take my phone out of my pocket so they sent me back out to put it in a bowl and when I went back through I got the "random" three beeps and got sent to the scanner. Oddly enough even though there was nothing under my shirt it still 'hit' on two places. The TSO just waved me on through after I pulled my collar down showing there was nothing there.