From my experience in theaters... (Score 0, Troll)

I can't say that I can recall ever hearing an annoying cell phone ring while watching a movie. Or, any cell phone ring for that matter.

I do however think someone needs to invent a loudly talking group of obnoxious black people jammer. Or, maybe just a "Please make sure that your black people are switched to silent or turned off" courtesy message at the beginning. Seems to work for the cell phones.