Having to argue that demos don't need marshalls wearing reflective vests...
Anarchists have held a hundred demos here in the last decade and our tools have always been self-organization and autonomy in the streets, not creating a group of people whose job is to manage the crowd.
Yes, you want some people to show up planning to hold the front and back and sides, some people who shut down intersections, but these people don't need to specialize, set themselves apart from the rest of participants. Because anyone can do it and in fact we want anyone to do it.
The difference between a crowd and a social force is self-organization. The whole purpose of demos, to me, is to increase self-organization and combativity, to become a force. It might seem like I'm exaggerating, but importing a practice of marshals to our scenes goes in the opposite direction.