No member of the Board or the Panel, or the General Counsel, or employee of the Authority, the Federal Service Impasses Panel, or the General Counsel shall produce or present any files, documents, reports, memoranda, or records of the Board, the Panel or the General Counsel, or testify in behalf of any party to any cause pending in any arbitration or in any court or before the Board or the Panel, or any other board, commission, or administrative agency of the United States, territory, or the District of Columbia with respect to any information, facts, or other matter to their knowledge in their official capacity or with respect to the contents of any files, documents, reports, memoranda, or records of the Board, the Panel or the General Counsel, whether in answer to a subpoena, subpoena duces tecum, or otherwise, without the written consent of the Board, the Panel or the General Counsel, as appropriate. Whenever any subpoena, the purpose for which is to adduce testimony or require the production of records as described in this section, shall have been served on any member of the Board or of the Panel or employee of the Authority, the Federal Service Impasses Panel or the General Counsel, such person will, unless otherwise expressly directed by the Board, the Panel or the General Counsel, as appropriate, and as provided by law, move pursuant to the applicable procedure to have such subpoena invalidated on the ground that the evidence sought is privileged against disclosure by this rule.