That's all pretty much the point.
If it's a short term natural disaster...which in Arizona is extremely rare, there is no reason why I wouldn't man the chainsaw or help with LE or other "civic duties". Alas... We don't have tropical storms, tornadoes, hurricanes, blizzards, etc...
I am talking about a true SHTF scenario and it is SERIOUS.
There is definitely strength in numbers, but only if you can trust the numbers you are with.
My LDS neighbors...as good as they have been as neighbors, certainly would "clan up" with other LDS to the excllusion of other non-LDS. If I understand their precepts, they already have a plan and command structure within their ward (local chuch body) for that.
I am all for being the good neighbor. I am decidedly NOT all for being the welfare-supply depot if it has turned to crap.