Sony Pictures is under fire from a group calling itself "Guardians of Peace" or for the Twitter crowd, #GOP. The GoP is now threatening to physically attack movie theaters that show a particular film, The Interview. An interesting twist, that seems more and more unlikely as time passes, is the rumor that North Korea is behind the release of proprietary Sony data, as well as the threats to theaters.
Another theory is disgruntled employees, which sounds much more plausible and it has plenty of historic precedent. In the movie business, it has a very violent precedent that goes back to at least the 1920s. The book "The Perils of Movie Going: 1896-1950" highlights plenty of incidents. Full disclosure: I have not read the book, it came up in my research and the index is quite thorough.
One string if incidents was the Movie Union War in late 1920s and early 1930s Chicago, waged by Theater Operators Union boss, Thomas E. Maloy. Numerous movie houses were attacked, with dynamite, in an effort by the movie projectionist union to have two projection operators on every shift. Below are but a few of the headlines:
"Bombs, Bullets, and Blackmail"
"Bombs Burst at Three Movie Theaters"
"Chicago Movie Houses Closed in Union War"
One can even purchase old file photos from newspapers. This one captured the 13th theater bombed in 1931:
From Haymarket to the Movie House Union War, Chicago has endured the hellish marriage between labor unions and explosives. Later, that shifted when the unions dropped the bombs and political factions like the New Left picked them up. For example, the book and documentary I am working on, Time Bomber, about a 1971/72 bombing plot, had no labor component at all. Neither did the 1975 FALN bombings in The Loop.
With the new threats against theaters, probably by disgruntled employees, it seems the pendulum has swung back to its violent origins.