I like what someone said earlier re: Vanuatu could have worked that out themselves, however I can't help but feeling that someone spilled the beans there.
Let's face it, is it what teams who are underdogs in big games do regularly, to check the opposition squad for possible breaches of FIFA regulations? And if Vanuatu had done just that, how could they know that we hadn't received clearance for the player to compete in the U20 World Cup? At the end of the day, he only played for the U20 less than a month ago - you would expect everything to be jolly good on the eligibility front.
If you're an outsider doing your work on Wikipedia or Transfermarkt you could find out that he was born in SA, but you wouldn't necessarily know everything else, would you? What if he was a refugee?
I love a good conspiracy theory and the more I read and think about this, the more I think (and quite frankly, hope) that someone has fudged us from the inside. Don't believe OFC did that on purpose or anything, but given our comments on the tournament and its set-up, they probably enjoyed the opportunity to stick a finger up there where the sun don't shine.