It's right in the abstract: "TSA is updating the AIT PIA to reflect a change to the operating protocol regarding the ability of individuals to opt opt-out of A

It's right in the abstract: "TSA is updating the AIT PIA to reflect a change to the operating protocol regarding the ability of individuals to opt opt-out of AIT screening in favor of physical screening. While passengers may generally decline AIT screening in favor of physical screening, TSA may direct mandatory AIT screening for some passengers."