The policy may provide that the insurer is not liable, or is liable only in a reduced amount, for losses arising from conditions:
(a) Relating to war or act of war;
(b) Relating to military or naval service;
(c) Relating to aviation.
The commissioner may after notice and hearing prescribe reasonable rules and regulations relative to the use of provisions permitted by this section in respect to policies outstanding or hereafter issued.
(Added by Stats. 1943, Ch. 909.)