Wirelessly posted (iPhone: Mozilla/5.0 (iPhone; CPU iPhone OS 6_0_1 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A525 Safari/8536.25)
I occasionally get my hands swabbed at a PreCheck lane. Twice at LAX, once at PDX.
The PreCheck lane was broken one trip through LAX so everyone had to go through the regular screening.