Flying with my wife, both in trusted traveller program, I had this printed on my BP but my wife did not. I understand it is quasi random and not all the time so we figured it was her time. Suprisingly, she got the single beep but the TSA agent looked at her screen for a few seconds and waived her through anyway. I got the three beeps and we went in together. Oh, and the Precheck lane was longer than the other regular lane