Yeah I'm sure he blurted out that he's in a game that he signed a NDA on. It's not like Nintendo told him not to talk about it or anything. And I'm also sure he'd leave the interview link up on his twitter with that statement even with the story spreading around, and people asking him about it.
I obviously could be as wrong as I think you guys are, but sometimes if it quacks like a duck, and then says it's a duck.....
Hey if I'm wrong, cool, sounds like you guys want him involved (or Raiden and Snake) and I hope you get who you want, but this really seems like a mistake, hope you guys don't get excited for nothing :/