To me the underlying issue with any of these scenarios is people. A single human being is intelligent, clever and in general can be dealt with. People, however have the tendency to act like fcktards when the SHTF. Therefore, my main concern is not zombie, virus, meteor, tyrant, government, food shortage, no hairdryer, whatever... My main concern is keeping the muzzle pointed at all the dumbass people who will panic, lose their sense of morality, and in general act in any way that endangers me and my loved ones.