I think the time travel hint was a bit too strong. I basically had two possibilities: H&C is a time traveller with all the world breaking implications, or Eliezer is meta-screwing with us. There's no other high probability reason for H&C to say that right before he obliviated Hermione. If the latter, all other bets are off - I can't seriously approach predicting a work like that. So I'm very glad Eliezer let us know.