When I saw Shutter Island (at BAM, even), I moved rather than endure the couple behind me's conversation, which ran, pretty intensely, for nearly the entire movie. You'd say something, but for shaming to work people would have to have any idea they were doing anything wrong—instead they'll just roll their eyes at you like you're some kind of contemptible snob or pansy.
In Lancaster, California two weeks ago, a guy did speak up when a woman sitting near him talked on her cell during Shutter Island. She and her two male companions left the theater; then the two dudes returned to the theater, and stabbed the man in the neck with a meat thermometer.
A melee broke out, because, you know, Shutter Island, madness in the air.