According to the regs, as PIC you have the emergency authority to "exclude any any all persons" from the flight deck in the "interest of safety" with this reg in place could you in theory deny a fed or a LCA from the flight deck in the interest of safety? Im sure that you would have to explain for it but could you say you did it in the interest of safety as you were not up to doing a LCA ride or a fed ride? Might be a stupid question but Ive always wondering if anyone ever tried to deny a fed or LCA under the guise of emergency authority.