N.Y. Comp. Codes R. & Regs. tit. 9, § 5319.24 – Bill validator stacker requirements.

(a) the bill validator device shall have the ability to detect a stacker-full condition; and
(b) there shall be a separate keyed lock to access the stacker area. This keyed lock shall be separate from the main door. In addition, a separate keyed lock shall be required to remove the bills from the stacker.

Each bill validator shall have a secure stacker and all accepted items shall be deposited into the secure stacker. The secure stacker and its receptacle are to be attached to the gaming device in such a manner so that such stacker and receptacle cannot be removed easily by physical force and shall meet the following rules: