The title is based on the Who's on First? comedy routine made famous by Bud Abbott and Lou Costello. The basis of the sketch is that Lou Costello does not understand that name of the first baseman is Who. What is on second and I Don't Know is on third.
When talking with Venus about not being able to flee to Mexico because his passport is expired, he says "Do they have illegal aliens IN Mexico?" showing that the term "illegal alien" is not a modern turn of phrase.