A movie theater industry group and the Motion Picture Association of America updated their anti-piracy policies and said that "wearable devices" must be powered off at show time.

"Individuals who fail or refuse to put the recording devices away may be asked to leave. If theater managers have indications that illegal recording activity is taking place, they will alert law enforcement authorities when appropriate, who will determine what further action should be taken," said a joint statement from the MPAA and the National Association of Theatre Owners, which maintains 32,000 screens across the United States.

The announcement should come as no surprise. Last year, the MPAA urged theater operators to crack down on movie piracy with the use of night-vision goggles, security cameras, and low-light binoculars. The MPAA's "Best Practices to Prevent Film Theft" also urged theater operators to perform "random bag and jacket checks" of patrons and to "look for the unusual."

The joint statement Wednesday, meanwhile, said "we maintain a zero-tolerance policy toward using any recording device while movies are being shown."

The statement did not mention Google Glass by name, but it didn't have to. The computerized eyewear appears to be an enemy of the movie industry. In June, for example, a cinema trade group representing most UK movie houses urged its membership to ban Google Glass. That same month, Alamo Drafthouse, with theaters in Colorado, Michigan, Missouri, Texas, and Virginia, was among the first US movie houses to ban Google Glass during movie showings.

Under US law, those caught recording a movie in a theater face a maximum three-year prison sentence. As many as 41 states have laws against in-theater recording, too.