canteen of water, not only do you get thirsty in a protest if it turns ugly wet a large do rag and cover your face. keep a can of softdrink and a sock in your pocket. By themselves it cannot be considered a weapon but a tube sock full of coke is a great equalizer. Keep $50 in your pocket as your bail will prolly be 500 and the bondsman doesnt have to wait for a 3rd party to get to you to pay him. Keep a few quarters for payphones. Let someone know where you are going. Always plan escape routes during the protest.
thanx,
bill