And when you get there to find them fully occupied or empty of goodies by the other millions of you?

And when the resources of the local and regional Red Cross, churches, etcetera, are gone, I ask again are you assuming the government can and will adequately respond?

We can continue this infinite regression [you post a what if and I counterpost a what if not], but I guess it comes down to this: do you prepare for the potential for evacuees and refugees overwhelming local resources as if it was in itself a disaster or emergency, or do you think your preparations for other disasters and emergencies covers the situation.

I propose that you think through the first possibility. If you have done so and decide that scenario is too unlikely or that you are already prepared for it with no changes, fine.