@bob Yes and no.  I think that this confuses symptoms for the root cause.  The root cause is inequality between nations.  Even with weak border controls there will always be borders of some sort, be they the checkpoints of countries or the unspoken boundaries of social groups.  When there is inequality between large groups, you will always see the stronger group in that context exploit the lesser one.  It is, sadly, human nature.  Some of us are better than that, and altruistic, but they are not a majority.