They now have body scanners, fixed and mobile (on a van or truck with cameras and scanning everyone on the street, it's been used at the Super Bowl, NFL games, and other sports and concert events without your knowledge), at bus stations, subway stations, train stations, that scans 2000 people per hour and look for signs of fidgeting, sweat, unusual behavior like not making eye contact with other people, raised body temperature, nervousness, perspiration, standing away from the crowd, and then tag them and put them into the system to ID them from the databases of driver's licenses so they can put on the no fly list for 90 days.
Remember the movie Minority Report where they can prevent crimes and murder from happening using biometric data from scanning people.
That machine now exists and it's coming too.
Also look up TSA Blue Skies program.
http://fortune.com/2018/07/30/tsa-qu...-surveillance/