In some cases I would like to make sure that an OP is notified of a comment I make (because, say, the comment is in some way a request for more information).
I expect that if I comment directly on their question, they will be notified (tell me if I'm wrong).
But I don't think that a comment made on an answer to their question will trigger a notification. At least not based on my experience as an OP.
So if they comment on an answer I've made to their question, and I want to respond to their comment with a comment, is there any guarantee that they will be notified of my comment?