But also as Malcom X said 'There is no such thing as a non-violent revolution'. They will, eventually, open fire on you if it actually looks like you're getting somewhere.
Edit : I think, that not only considering revolutionary history in general, but also what is happening (and has happened) in our present time with the 'arab spring' movements, that to argue that non violent revolution is possible is er.. churlish. Same goes for defending yourself on a peaceful protest, just how many times can you be hit with a stick before you'll think about hitting back ?