NYPD and FDNY helicopter traffic seems to be most noticeable during the summer months, in part because residents have their windows open and can hear them operating.
People then utilize online media to try and figure out what situation the helicopters are responding to, and whether they should be afraid. I've watched the phenomena with some interest over the past few years, because I have a belief the people may be better off not knowing of the situations, and would be blissfully unaware if there wasn't a noisy helicopter overhead to make them wonder and worry.
As technology advances, the use of expensive, noisy helicopters is poised to decline. Shot spotter microphones, quickly deployed agency-operated internet-enabled cameras, drones and other technologies are rapidly maturing. http://www.governmentvideo.com/article/fdny-employs-video-for-quick-decisions/115853http://www.nydailynews.com/new-york/nyc-crime/nypd-drones-fight-crime-article-1.1799980
All of which may allow NYC agencies (FDNY, DOB, OEM and NYPD) to operate in ways which do not arouse the "traditional" public anxiety and curiosity, and instead create slightly different forms of it...