Jim Emerson blogs about the warning affixed to a movie theatre's screening of Terence Malick's "The Tree of Life." It's not like the MPAA's warnings of violence and sex, but a warning that the film is arty. It may be too arty for some folks.
I figure that if you are making the choice to watch "The Tree of Life" then you already know what you're getting into. It's Malick. You should know by now his M.O. His movies are what they are.
That being said, I wish there was a warning for Bad Teacher. To wit: "Warning: Watching Bad Teacher has been known to cause cancer in lab rats."
http://blogs.suntimes.com/scanners/2011/06/detour_theres_an_arty_road_ahe.html