I can almost guarantee that this is exactly what they are thinking.
Yeah, punching people, kicking windows, getting arrested, standing around, and being hit by tear gas are WAY worse when it's approaching freezing.
Plus it gives the military, er, local PD, and national guard time to fortify and surround and really measure up the cowd, so they're ready to fck people up when the riots happen. Which they won't.
I'll say it - "riots" will be just like zimmerman, a few idiots acting big for TV, and a bunch of talk radio drama queen bitches hamming it up. People will yell and bitch, but they love going home and counting the likes on their FB wall, way more than they like sitting in a jail cell for political activism. Generation selfie will be home for the Daily Show, they aren't going to jail tonight.