The disruptors have been infiltrating the events. A little more discretion (read: profiling) needs to be done to winnow out the troublemakers.
But the point about setting out the limits and decorum is good and then adding that anyone who does not abide by these rules will be trespassing and told to leave and if they do not leave then they will be arrested. Trespassing is only a misdemeanor but we have to start somewhere.