Along these lines, I should say that I was startled by Molly's post which provided the reason for Ron to be at Hogwarts through the holidays. I had not expected that given the differences in the game. So that's what made me begin to think we might see a sudden reason crop up for Harry to stay. (I just can't really imagine how that would be made to seem necessary short of a major rebellion cropping up that can't be surpressed in a night or two...)