It probably depends on where you live. Some places have more active (or any) RCP groups. I don't really know what the context in NYC is, but where I live the RCP (and Oct 22nd Coalition which is a front group for them - this apparently isn't the case everywhere, but I would use caution when engaging with them) are, while ineffective at actually doing anything, rather adept at co-opting events to their own ends. I think they officially organized one event, but they show up with signs and megaphones and try to direct the crowd, while also making sure they create photo ops promoting their stupid website.
The protests themselves have been organized by a more fluid group - lots more young people of color, and some hold-overs from Occupy who have gone the community organizing route (and are revelling at the chance to be organizers and mouthpieces for something), with numbers bolstered by a lot of other folks I've never seen before and the usual anarchists and other rebels.
You asked about exception versus rule - I would say that if you live in a place where a Maoist cadre is active, the rule would be: Expect them to show up and try to manage and lead the rebellion into something more controlled, symbolic and authoritarian. They view themselves as the politically educated minority who have to help create conditions for revolution (using all us lumpen prole as pawns), and they should be confronted, or otherwise marginalized as a threat.