Once or twice a week it's normal to see Q-4's and Q-9's usually around the coasts or the border. There was a British Q-9 in South Arizona a couple of weeks back. The New England coast where you are focusing has had them frequently off of NJ, NY and occasionally Chesapeake Bay area. Have seen them on the North border too.

Not all that rare, but more common across the pond.

I've never seen one squawking it's position that I can remember. However, they may be required to if they're operating over high traffic areas of the country when they are operating state side. I don't know one way or the other. Just sharing and spitballing.