Nato helicopters

What with NATO being in Chicago, over the last few days there has been this trio of Hueys flying above an area near where I live in the suburbs. Yesterday I took a gander through some Binoculars at them and saw they had the doors open on one side and there were guys seated with their feet on the skids. Couldn't tell if they were holding weapons, but considering I live near a major tollway and the secret service command post is supposed to be in a suburban office building or park, I wouldn't be surprised if that is what they were keeping an eye on since there are several office towers not far from where I live. 
