Security theatre this isn't. More like the security Rocky Horror Picture Show.
Without the callbacks from the captive audience because those on stage might decide to shoot you.
A couple of days ago Xeni Jardin of Boing Boing flew into Los Angeles International Airport and was caught up with a large number of her fellow passengers in what could best be described as a game of anti-terrorism freeze tag run by the Department of Homeland Security. It went down a little something like this: Jardin and other travelers walking through a hallway after leaving the plane (probably the covered gantry that leads from the boarding platform into the airport terminal (the so-called secure area)) were commanded to freeze in place by armed DHS agents and private security personnel who blocked off the corridor. Anyone who tried to go anywhere, even if it was to sit down in a nearby chair was screamed at by security to not move. This went on for a good thirty minutes without any real explanation - "security review" doesn't cut it in my book, thanks. If you're going to hold a home team action review, involving civilians is going to complicate matters needlessly because they won't have any idea of what in the hell is happening to them, and some of them just might interfere with the stated exercise. Sadly, nobody did, presumably because airport security teams these days tend to be armed and willing to put days worth of hurt on your lifestyle for daring to ask the question "Why?"
If you read the comments to this article, LAX isn't the only place that this has happened. People have reported going through it at Portland International (PDX), Nashville, and Orlando.
I think that one of the commenters to that post is on the right track: Airport security does this to scare the hell out of people and see whom they can make panic and make a run for it.