From the looks of the aircraft, it is likely 160th Special Operations Aviation Regiment (Airborne). These guys have been doing this sort of realistic training in civilian areas since the 1980s. This is not new.
I served in an air cavalry unit in the 82nd Airborne and had two buddies go on to serve as pilots in the 160th. My closest friend flew for the 160th for ten years and went on to head aviation for Delta prior to retiring. He is a civilian contractor for the military today. He has been regaling me with stories of these types a training missions for years. They were ongoing through the Clinton and Bush years as well. These are the black helicopters you have heard of.
Now, I get the paranoia. My degree of trust in the federal government is at an all time low and this sort of thing makes me nervous too. It is a sad state of affairs that, as a veteran of Army aviation, a graduate of several SOCOM schools and a member of the American Legion, I am now made nervous by training that I used to support with pride.
Still, everyone should try to relax. This is not new. It is probably just more of the same. Probably.
Hat tip to Burd Dog for the link.