Nothing will fucking happen. Civilian law enforcement leadership gets rock hard when they're invited to be part of a federal task force, and will break their backs bending over backwards to accomodate the feds. On the bright side, last I checked, FEMA isn't a law enforcement agency, they don't have arrest powers, and they have no authority to seize propery from citizens. There is no citizens arrest in NC either. So it's really just some asshole, possibly armed, trying to steal your shit. Maybe don't let them.