*While this is about Precheck, I think it is appropriate here as it is about Checkpoint policies.*
Recently TSA Administrator Peter Neffenger stated:
"WE'RE PUSHING A LOT OF
THOSE PEOPLE BACK INTO SCREENING SECURITY DUTIES THIS SUMMER."
"Those people" (how personable of you Neffenger) are Behavior Detection Officers. A few articles have mentioned have mentioned that "these people" will be staffing TDC positions.
H.R.5338 - Checkpoint Optimization and Efficiency Act of 2016, which is currently in a US Senate Committee, would require that "those people" staff TDC on Precheck lanes.
This would mean, you are Precheck - the majority of Precheck having undergone a background check, interview, fingerprints searched - would be subject to "those people", as explained on The TSA Blog:
Behavior analysis is based on the fear of being discovered. People who are trying to get away with something display signs of stress through involuntary physical and physiological behaviors. Whether someone’s trying to sneak through that excellent stone ground mustard they bought on vacation, a knife, or a bomb, behavior detection officers like me are trained to spot certain suspicious behaviors out of the crowd. Once we make our determination, we refer these passengers for additional screening or directly to law enforcement.
So despite being vetted, TSA and Congress feel the need to subject this vetter population to "those people" because vetted populations are "trying to get away with something" and have a "fear of being discovered".