Apparently, this is not unheard of in airports:
And a half-dozen commenters have similar stories. [Boing-Boing now with comment moderation by Teresa Nielsen Hayden.]
I walked from the arrival gate towards baggage claim, and when I was about halfway there, all of a sudden about a dozen or more TSA personnel and private security staff appeared, shouting STOP WHERE YOU ARE. FREEZE. DO NOT MOVE. Not just at me, but all of the travelers who happened to be wandering through the hallway at that moment.
Some of the TSA guards then backed up against walls in the hallway, and sort of barked at anyone who tried to move a few feet away from their "spot," like towards chairs to sit down or whatever.
One TSA guard jogged ahead, back towards the arrival gates (United, this was Terminal 7). At first I assumed maybe it was some weird security drill? A few of us asked what was going on, and got terse answers, like, "Security review." WTF? 5 minutes passed. 10, 15, 20. The two teen Japanese tourists about ten feet behind me looked utterly dazed -- welcome to America, guys. I was really jetlagged and cranky, wanted to move a few feet and sit down, but the TSA lady nearest me kind of snapped at me to stop and stay frozen where I was when the order went out.
After 30 minutes, the TSA people said, okay, you may leave now. And everyone unfroze, and went and got their bags. No explanation. I guess I should have pressed for an explanation, or demanded to know why we were being held without our consent and without a provided reason, but I was really tired and just wanted to get the hell out of there and go home. Perhaps I was wrong to have just walked away.