DAVIS, CA - NOVEMBER 21: A sign with a picture of a pepper spray canister is posted on a tree during a demonstration at the UC Davis campus on November 21, 2011 in Davis, California. Thousands of Occupy protesters staged a demonstration on the UC Davis campus to protest the campus police who pepper sprayed students sitting passively with their arms locked during an Occupy Wall Street demonstration on November 18. (Photo by Justin Sullivan/Getty Images)

DAVIS, CA - NOVEMBER 21:  A sign with a picture of a pepper spray canister is posted on a tree during a demonstration at the UC Davis campus on November 21, 2011 in Davis, California. Thousands of Occupy protesters staged a demonstration on the UC Davis campus to protest the campus police who pepper sprayed students sitting passively with their arms locked during an Occupy Wall Street demonstration on November 18.  (Photo by Justin Sullivan/Getty Images)