This is true. Per NYC DOT: "No person shall operate a bicycle unless it is equipped with a bell or other device capable of giving a signal audible for a distance of at least one hundred feet, except that a bicycle shall not be equipped with nor shall any person use upon a bicycle any siren or whistle."

There are no helmet rules listed that apply to anyone over fourteen.

Source: http://www.nyc.gov/html/dot/downloads/pdf/bicyclerules_engli...

> There are no helmet rules listed that apply to anyone over fourteen.

This is untrue; commercial cyclists must wear a helmet (see 412(p)(4)(v))

Fair enough. They also are supposed to wear retroreflective jackets that identify them and their employer.