That New Black Panther thing in Philly in 2008 might have been testing the waters. I expect to see a whole lot more of it in 2012.
These flash mobs are being orchestrated and coordinated by someone. They're happening all over the country, and I don't believe it is a coincidence. Somebody is trying to provoke a race war, and it isn't "whitey".
ETA: Heh. I wrote my above comment here before I saw #37 and 38 over there. Looks like I'm not the only one thinking along these lines.