I've been out at Penn State University during two student led riots. PA is a state where concealed carry is legal (and some what prolific) and is now a caste doctrine state (meaning you have no legal requirement to retreat when life or property is at risk). Despite that, firearms never once came into it.

Rather, the police are pretty good at identifying and arresting the real trouble makers of the group before they really get out of hand. From what I saw, their tactic is basically to saturate the area with police, grab the major trouble makers, and use OC spray when necessary for protection. They more or less get right into the middle of the riot. This seems a bit different than what I've seen on tv of UK riot control, where they prefer to stand off a bit more.

Also interesting, was their significant use of horses and dogs. K9 officers and rows of horse mounted officers were used to essentially contain the crowd in an area where the least amount of damage would be created. They basically pushed the crowd where they wanted it and pulled out the real troublemakers.

They were surprisingly efficient at it as well. I saw a shop window get broken and, within a minute or two, there were more cops outside the window than rioters.