If the Vow prevented him from letting Draco know on a permanent basis for this reason, it would prevent him from telling him with the intention of obliviating him afterwards, since there would be a chance he would get away without being obliviated.
Good point. He's counting on Minerva to obliviate Draco, which makes it a bit safer.
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 120.
Plans for next chapter release:
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.)