N.Y.C. Admin. Code § 20-304: § 20-304 Licenses to be displayed.

Every licensed locksmith shall display the license issued hereunder in a conspicuous place where it can be readily seen by anyone entering the premises where the business is conducted. Where the licensed locksmith is not in business for himself or herself but is employed by another, it shall be incumbent upon the licensee and his or her employer to display the license hereunder in a conspicuous place where it can be readily seen by anyone entering the premises wherein the business is conducted. Where more than one locksmith is employed in such premises the license of the person then in charge need only be displayed. In the case of an itinerant locksmith the license shall be on his or her person or prominently displayed upon the working kit he or she may carry or upon any vehicle which he or she may use in the plying of his or her trade or occupation.