I don't see how this is a problem. Do you think it is a problem ? If so, then why specifically and do you have any ideas for a solution?
To be fair, it's really hard to figure out WTF is going on when humans are involved. Their reasoning is the result of multiple motivations and a vast array of potential reasoning errors. If you don't believe me try the following board games with your friends: Avalon, Coup, Sheriff of Nottingham, Battlestar Galactica, or any that involve secrets and lying.
Edited phrasing to make it more clear....
Your phrasing makes it also look like a plausible mistake for someone in a new situation with little time to consider things.
A story for the masses is necessary and this doesn't appear to be a bad stab at one. Harry can always bring trusted others on board by telling them what actually happened. He might have actually done that already and this is their plan. How much time did Harry have to do stuff before needing to show up anyhow (40m? 50m?)? Also, Prof. McGonagall is terrible at faking anything so telling her the truth before this seems like a bad idea.
Lucius is both dead and warm. I think he's dead dead unless Eliezer has someone like Harry does something in a very narrow time window. Dumbledore is a much easier problem to solve (story wise) and can be solved at the same time as the Atlantis story thread if that is what the author plans.
If you want to make the scenario more realistic then put more time pressure on Voldemort or put him under more cognitive stress some other way. The hardest part for Voldemort is solving this problem in a short time span and NOT coming up with a solution that foils Harry. The reason experienced soldiers/gamers with little to no intelligence still win against highly intelligent combatants with no experience is that TIME matters when you're limited to a single human's processing power. In virtually every combat situation one is forced to make decisions faster than one can search the solution space. Only experience compensates for this deficit to any measurable degree. In this situation there are several aspects that Voldemort does not have experience with. If he must spends his cognitive resources considering these aspects and cannot draw from experience it makes mistakes much more likely.
I begin to wonder exactly how the story will be wrapped up. I had thought the source of magic would be unlocked or the Deathly Hallows riddle would be tied up. However, I wonder if there are enough chapters to do these things justice. I also wonder whether Eliezer will do anything like was done for Worm where the author invited suggestions for epilogs for specific characters.
I see your point, but Voldemort hasn't encountered the AI Box problem has he? Further, I don't think Voldemort has encountered a problem where he's arguing with someone/something he knows is far smarter than himself. He still believes Harry isn't as smart yet.
Yes, yes there is :). http://boardgamegeek.com/boardgame/37111/battlestar-galactica