What does an inactive Glass look like under infrared light? It probably glinted a ton on some recording device, someone noticed, he was detained. And they did say, word for word: "You were caught recording the movie".

Advice: Don't point what's basically a cheap webcam at a theater screen for the duration of a movie and not expect to get yelled at.

The legal side of this that everyone is discussing is the result of a failure on the technical side which hasn't even been figured out yet.