One thing that may be happening (or start happening) here with these bus protests is that unrelated leftist groups from the Bay Area will seek to piggyback on to this and cause havoc. This is a definite trend if you follow political action in Northern California.

By far one of the most notorious offenders are the "Black Bloc" anarchist groups. One of their codewords during protests is "direct action" which means "break stuff, smash windows." I can't say anything about their political views, but it's a fact that they attract a greater and potentially more violent police presence.