N.Y.C. Admin. Code § 10-705: § 10-705 Signage.

The operator of a venue as defined by paragraph (2) of subdivision b of § 10-701 of this subchapter may prominently display at the entrance to such venue, a sign stating in conspicuous letters that are at least three-fourths of an inch high that the unauthorized operation of a recording device at such place of public performance is prohibited by law and is punishable by criminal and civil penalties.