Some people are making suggestions on this thread, as well as giving advice such as:
"Cops in riot situations are there to subdue you, get you on the ground, and have the second line immobilize and detain you. With their batons, they aim for your mid section/sides and front of the thighs. You can easily protect against this in a ghetto way by wrapping thick maqazines (more GQ than Us Weekly) around these areas. Nothing pisses a riot cop off more than when they smack you in the stomach and nothing happens. If you're planning on staying put and are holding on to something, they'll smack your hands. Motorcycle gloves help in this situation."
http://boards.4chan.org/diy/res/67305I hope this info might be useful to somebody.