I was kidding... But, I have friends who did have to defend the hill their houses were on, during one of the (now apparently annual) massive brush fires that swept through the southern hills of California. The looters did come, before the fires were even a threat. They left when they found themselves staring down the muzzles of a few guns. It certainly helps to be prepared.
WRT a shotgun for community defense, I think it's also important to remember that buckshot retains its ability to injure and kill long after the pattern has spread to be wider than a human target, which can happen at a relatively short distance outdoors. Therefore, in the interest of being responsible for every bullet I shoot, I would not use a shotgun, especially in a cylinder bore, for most community defense scenarios. Obviously, if you have a good backstop, or there's nothing and nobody within a few hundred yards, this isn't as much of a concern. But in a populated area, I'd really give thorough consideration to how and where a shotgun could be fired.