Shouting 'fire' in a crowded theater?

Last week, an Oklahoma City man was pulled over by police for having an anti-Obama sign on his car. The sign said "Abort Obama, not the unborn." Police pulled the man over and confiscated the sign, even though the motorist said that he believed the sign to mean that Obama ought to be impeached.Here in Israel, we're way ahead of that. During the Oslo War, there was a very popular bumper sticker