The "captain's authority" you keep spouting off, has absolutely nothing to do with who is allowed in the jumpseat other than to permit or deny people who the company has already allowed this privilege. If the privilege is gone, it is gone. Your "captain's authority" won't do you any good then. You have forgotten the big picture - the company or the investors own the airplane. Your job is to be a professional and get the passengers safely from point a to point b.