The national guard was brought in to man checkpoints at every road leading into one of our disaster areas. That's pretty much all they did unless one of the local politicians was concerned that the people in their area were going to "start trouble" (i.e. try to do things on their own rather than going through gov't agencies). When they got worried about that they would threaten to bring them in to "keep order" but I never saw that actually happen.
In my opinion/experience, the more control the locals have over how things are done the more smoothly everything will go. However, knowing the reputation of the NYPD, it may not be a bad thing for the actual survivors if they were to allow the guard to have some access. It could work in their favor. IDK... it still frustrates me to think about how much more difficult things became for us once the government arrived and insisted they were in control.
Ron Paul convert from the Heart of Dixie