That's actually something I hadn't thought of, and a good point. I suppose it's possible that an idea that was in the first category could've been so fundamental that they couldn't write around it! Of course, I'm inclined to then say that the lesson learnt from that should be "Don't start writing an even slightly collaborative idea until you know that the other person isn't a crazy asshole" then XD Not to mention that doesn't exclude it from being in the second or third category.