Yeah, that's kind of the way I'm seeing it. If there's going to be a prize, it'll probably be for the first person finishing the riddles. Therefore, if a few people have already finished it, there's no harm in helping others figure it out.
If it's a random sampling of who's finished the riddles, then it doesn't matter that much if a few more people are in on it.
And honestly, I'm just having a good time solving the riddles (Except for the 'rational' one).