Has anyone ever stopped for a moment and wondered why there was no such thing as an "illegal alien" in Biblical times? Once you understand why this was the case, you'll realize why this is such an idiotic issue to contest on religious grounds.
I'm going to plead ignorance of the laws of the ancient world yet there are at least two reasons why I think that the various societies were concerned about "aliens"
(1) They built expensive walls around their cities
(2) And if one wants to get "Biblical" about it, think real hard about the point and purpose of the event at Babel. We can speculate all day on specifically why there was the dividing of men into separate and distinct nations, but with the abundance of empirical evidence the fact is clear there is such a thing as Divine Apartheid. I submit that no matter how much the misotheists wish to social engineer an anti-Babel system, the nations will always be suspicious if not down-right hostile to "foreigners". Xenophobia is as old as Babel and will be with us (at least in its secular sense) until the 2nd Coming.