Originally Posted by lincolnjkc

Fiancée (not PRE) and I (PRE and GE, though I use the PRE KTN since I had that # first) have had mixed luck.

I've had 100% success with PRE on all trips [including when I've been INVOLed to another airline], when she's traveling with me...earlier in 2016 it was hit-or-miss (maybe 50% success), end of the year 100%.

The airline hands over the record to TSA to make the go/no go determination, my guess is that there's some algorithm that looks at both individual risk as well as risk of traveling companions and gives the ^ if a low-risk traveler with a known traveler.