138. A lawyer who is asked by the Barreau to sit on the professional inspection committee, the disciplinary council, the review committee constituted under section 123.3 of the Professional Code (chapter C-26) or a council of arbitration of accounts established pursuant to the Regulation respecting the conciliation and arbitration procedure for the accounts of advocates (chapter B-1, r. 17) cannot refuse the position unless he has reasonable grounds to do so.