There are occasionally a few who use violence in a disorganized way without consultation however they aren't the majority of those who employ violence in protest actions. In my experience violent protestors such as the black bloc groups are well coordinated and plan their actions in advance, consulting with other protest organizers. They still use violence however, so for those who say "consult" but mean "unconditionally accept the liberal sentiments of other groups organizing protests" then there will still be some disappointed liberals in the crowd, or staying at home instead.