I think MedB raises a valid point.
Are you trying to order people to comply with your plan or are you trying to get them co-operating to solve a problem?
There are times where both approaches are valid.
There are also times when one or the other of these approaches just will not help.

The authoritarian approach does work to reduce confusion and situational paralysis, but the consensus approach often gives better actual plans to solve the emergency.

I guess if you are a trained medic/cop/soldier you are going to assume command of an emergency and tell the people around you what to do.
But in some cases you might be better to just help the people to organize their own response because they might know how to use local resources better once they understand which problems they need to solve.

EDIT:
In a lot of cases people are plenty smart enough to solve a problem, but don't have decision making skills because they have been taught all their lives to only do what they are told to do. So they need somebody to do that for them.