I was listening to something on the World Service about this yesterday and thought of Kent State as well.

It's interesting to see different countries' response to this kind of thing. I was accidentally caught up in a student protest in Paris once. French protestors are hard core and the Parisian police even more so. There's no messing around with negotiations, they just unload. I walked around a corner into a cloud of tear gas and had to get out of there fast. It's just lucky I avoided the rubber bullets.