(1) Every one, whether a member of the New Zealand forces or not, acting in good faith in obedience to orders for the suppression of any riot given by the senior constable for the time being acting at the place of the riot is justified in obeying the orders so given, unless those orders are manifestly unlawful; and is protected from criminal responsibility for using such force as he believes, on reasonable and probable grounds, to be necessary for carrying those orders into effect.