It's been like that since the mid-80s. Before we go tangential on NFPA, there has always been a policy (to my recollection - I've been out of the area for 16 years) that on fire (10-31), smoke (10-34), or multiple calls received there is a full response. What you heard was most likely a single electronic activation from a central station, or very possibly could have already been a confirmed malfunction. The high rise buildings have 24/7 paid maintenance or security people who might provide authentication.
There are thousands of housing and office units in high rises there, and overwhelming statistics over the past several decades. I know, the "just once" argument, but also consider that the borough employs many people who are volunteer firefighters who may not necessarily be dispatched, but may already be headed toward their respective stations. It's not unheard of to get an immediate upgrade in response after a 10-45 (activated alarm).
It might be interesting to know that Dubai, in the United Arab Emirates, has a very large number of high rise occupancies and has a similar problem with a high volume of false smoke alarm activations.
