Like you, Lant Pritchett has quickly become on my my intellectual heros. Yet, it makes me worried that he seems to breeze over the exploitation that unskilled guest workers may face in the migration process. If the wage differential is so high ad benefits of migration are so enticing -- then many more people will seek to migrate than actually migrate at any given point. Who goes and who stays? Perhaps the person who pays the most to a middleman or a recruiter.