FWIW, I really liked both the art and the content/intent of the artsy post.
I think that a “ranked game where the teachers is much stronger and wins” is precisely the exception that we want to make to the rule “no assistance in ranked games”, even though it is a cumbersome term.
I think that “RGWTTIMSAW are allowed” is a case that might warrant a clause in the TOS, because it otherwise does cause the ethical dilemma that started this post.
Note that in practice, if the teacher accidentally loses one of these (which is possible when concentrating on teaching, and especially in a handicap situation), the expected action would be “request an annullment”, IMO.
I will also note that there is one other exception that we want to make, which is “casual” assistance from the opponent, such as “hey did you mean to play self atari” or “would you like an undo? (*)”.
I think that “casual opponent assistant” is something that just does’t come up as a problem in practice, and is not ammenable to a legalistic description in TOS anyhow.
(*) although this particular question is not especially recommended .