This is, of course, a thought experiment and also a way to see if anyone can pass along their experience with this kind of thing in the real world.

Very remote areas with small populations and a commensurately smaller resource base are certainly less likely to find millions of folks showing up. But that does not describe the whole country - much less other countries.

Displaced persons with pressing family and personal needs, even without criminal attitudes, are going to stress resources where they land. Millions of them, with the best and most honest of intentions, could well feel forced by circumstance to do what they must to help their families and selves survive.

I would hope it never happens, but I thought it worthwhile to extend our thinking to consider if, at some point, such a flood of evacuees might themselves become a diaster or danger that we should in turn consider fleeing from them.