I cannot for a second imagine Moody allowing Harry to hold on to Tom Riddle. There are too many ways in which keeping a superpowered, immortal amnesiac former villain on your person could go wrong. Harry must anticipate this, so can't consult Moody.
Perhaps. But Moody did defer to Dumbledore, keeping Moody totally in the dark doesn't seem like a plausible option, and Harry explained to McGonagall in chapter 14 that he had enough common sense to seek out the appropriate experts in situations like this (or discovering Salazar's Chamber).
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 116.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)