Opening boarders? absolutely idiotic, especially with radicals like ISIS growing ever more bloodthirsty.

There will also be a mass exodus to First world nations such as Mexico to the Us and Middle Eastern nations to Europe (which is already happening). It would also encourage nomadism between countries.

The fluctuation of population would cause mass shifts in payments of taxes and imagine the differences in the space of years in politics because of the shifting demographics

Honestly sounds like the prelude to the apocalypse, pure chaos with no real benefits apart from more money being earned and fixing a minor breach in the Declaration of Human rights

EDIT: Also that article is referring to the movement of state such as Florida to California, a big difference