I had one bad experience at Boston Logan, I set off the metal detector (I think it was malfunctioning, a lot of people set it off) and every one of us that set it off was put in to the scanner line, which got huge really fast because the metal detector was acting up, and then I was stuck behind someone who was difficult and got hand searched and swabbed right there. Super irritating, but Precheck has been fantastic at several other airports, and my friends in Boston say that Logan tends to screw that stuff up fairly consistently.
Matt
My worst pat down experience was with precheck. I had a elastic hair tie with a 1 /16 of a inch metal in my hair. Was sent through the scanner, hot spots all over. Top of my head, The woman was patting my head like nice little doggy....My hair is thin enough, what could be on top of my head...anyway... waist, asked if I was wearing a belt, no....(the guy ahead of me was told to leave his belt on) ankles, feet, soles of feet,,,took my shoes to put through ex-ray. So glad my husband went ahead of me, at least he could retrieve the bags with my wallet in it.