When not participating ourselves, that is what we like to do. (Edit-go out and cheer, that is)
Because of a history of running, I usually notice and keep in touch with the signs that a race is 'fixing to go off,' but did Chris and the organizers have the media outlets discuss the road closures? There are always a few folks that get wound up when the roads are closed. In other cities I have lived in the news media are active promoters of the larger races because they not only pull in out of towners, but local folks can group together and encourage each other. When the Armadillo Dash had the aid station competition I absolutely loved that.
Anyway, good luck to all and we will cheer you on. We usually try to find a place w/o a lot of people so runners stuck in the mental abyss of 'why the h**l did I do this' and 'I should have/haven't done that long run two weeks ago' are hopefully buoyed along to the next group of spectators....