The showing of interest, including authorization cards where a petitioner seeks certification by card check, shall be confidential and shall not be furnished to any of the parties. The Director of Representation shall determine the adequacy of the showing of interest and such decision shall not be subject to collateral attack. Neither the nature nor the size of the showing of interest shall be divulged. The showing shall be returned to the petitioner once the case is closed.
N.J. Admin. Code § 19:11-2.1