IMO they could be, but the police deliberately were not stopping or identifying them so no prosecution is possible until the police and the University get their attitude adjusted. They are effectively encouraging the riots and beginning the steps toward an actual insurrection.
UC Berkeley, like most if not all UC campuses, has its own Police Department. Their police chief, Margo Bennett, is a lefty with a truly bizarre back story, and I doubt the UCPD would lift a finger for free speech...
http://www.dailymail.co.uk/femail/article-562141/How-Patricia-Cornwells-lesbian-affair-female-FBI-agent-ended-savage-revenge.html