Here's a video from another angle (long and boring). And I was mistaken - the cops were surrounded by the folks sitting in a circle (not just a line). And the group of kids blocking the cops are facing away from the cops. However, it seems the cops were able to move out of the circle easily. At 13:30 one cop takes a handcuffed girl off amidst fairly modest boos by the crowd.
In the guy's third video it shows the cops still surrounded, and one cop gives a couple of tugs on one of the guys on the sidewalk. Seems to me he didn't try too hard, and then the cop with the spray “steps over some folks” - then he sprays them. That is when the real ruckus starts.
In this guy's set of three videos there is a guy in tan pants and a white shirt that is roaming around and seems to be directing the kids. I think he was the one that directed the kids to get up and face away from the cops when they first set-up the circle. I suppose to show “non-violent resistance” and also to avoid a face full of spray. I hope he was one of those that got arrested and they find out what he is about. I imagine it is the typical small group of diehards that foment this stuff and use the students as cannon fodder.
Thanks for the link and comments.
On the third video at about 3:50 in, there is a guy who walks up to the seated protestors and pulls out a red bag with something in it- then he hands it to one (or some?) of the protestors. The cops make note of this, and a cop (facing the protestors) walks forward to take it away from the protestor, and he pulls at one of the protestors arms, but the protestor doesn’t give back whatever that object was.
After that, the cop who did the spraying steps over the protestors and starts the spraying.
So, it looks like whatever was handed to the guy (or the perception of a possible dangerous object), and the apparent hiding of that object is what caused the cops to take action, valid or not.
Part 3: http://www.youtube.com/watch?v=NwFa5Kq4Rfo