Stop and search
Presumably once the database and facial recognition are running a bit more smoothly this will be rolled out as an app for police who can quickly check on “random” stop and searchs if someone is a visa overstayer.
Or in an even more Orwellian move they could plug the system into some random CCTV traffic cameras within the US to fish these people out of the crowd.
Up until now AI has not been able to identify people within cars, but this is being worked on:
https://www.google.com.au/amp/s/www.theverge.com/platform/amp/2018/6/5/17427150/facial-recognition-vehicle-face-system-homeland-security-immigration-customs