I remember reading about an antiwar rally some years ago in Oregon where one of the protesters did this to an American flag, to cheers from onlookers. This is what happens when you don't toilet train your children before sending them off to college.
Stinking up Wall Street: Protesters accused of living in filth as shocking pictures show one demonstrator defecating on a POLICE CAR
UPDATE: Snowflakes in Hell has a video of one of the Occupy Wall Street protesters who is wearing--I kid you not--an East German border guard uniform as a statement about class warfare. Here it is, from YouTube:
As one of the comments over there put it, "Can someone escort these guys back to the Columbia University faculty lounge?"
Along the same lines, Michelle Malkin gives some amusing video of the various Occupy whatever protesters around the country who can't even read the signs that they are carrying--they were just paid to march.