Guess who is doing the identifying - CBP and ICE. Guess who runs borders and immigration, which is the use case for PreCheck and Global Entry?
Guess what the stated jurisdictional limits are for CBP? 100 miles from any possible border [https://legalclarity.org/immigration-map-of-us-jurisdictiona...].
Guess who has essentially unlimited jurisdictional limits? ICE.
So they can pretend they are ‘checking for immigration status’ using the existing photos and biometrics, while simultaneously gathering information on who is at what protest.
Then the info gets shared once gathered - with or without plausible deniability - and blam. Bobs your uncle.