[steveklabnik]

The idea is that people temporarily disperse and regroup elsewhere.

Often, things like 'free speech zones' keep the protest away from the actual venue of the thing being protested. In Pittsburgh for the G20, for example, we weren't able to get within two miles of the actual summit happening. Yeah, people saw the news, which was a bunch of images of people breaking stuff, but they didn't see that people started breaking stuff because the police started throwing tear gas. And using the LRAD.

Unfortunately, the geography here really sucks for this kind of thing, but in a more gridlike city, the main body of people could have dispersed and filtered through police lines.