The way I see it, Nintendo wifi never works that way. I've played both Mario Kart DS and Tetris DS, and both handle connections pretty much the same way. Assuming Metroid Prime Hunters, Animal Crossing DS, and every other DS wifi game in existance handles it the same, I see no reason why it would be any different.
It does raise an interesting question. I think that it'll be recorded by Nintendo only if all players agree on spectators. Not too sure, though.