I haven’t been following everything here, but I was really surprised to see this:
So, if I, say, point out a self-atari or a joseki mistake and offer my opponent an undo, it’s considered “outside assistance”? I never would have thought to consider someone else in the same game as “outside”. Sure, it might eventually add up to “rank manipulation” but occasional help seems so different if it’s offered openly by your opponent vs. taken secretly from AI.
By the way, regarding humble rank, my impression is that it’s completely broken for matchmaking and maybe always was:
EDIT: it does at least appear to be working for the “opponent rank range” feature of automatch.