Originally Posted by
volta
So I have an issue, as flew lately with US Airways and entered my PASSID at the time of checkin and my boarding pass didn't show TSA precheck (6 flights). Asked TSA agent why is not showing and he claimed that it has to be at the time of booking. One more info: don't have any status with US Airways
TSA employees at airports are, in the main, clueless about how PreCheck LLL outcomes happen and don't happen to come up for boarding passes. The KTN field can be completed after booking and still result in PreCheck LLL outcomes for the boarding pass -- I've personally observed and repeatedly done this for multiple passengers on AA, DL, UA and US flights and it continues to work even when using miles from a "loyalty" program of a non-US airline.