In our environment, I am always an "approver" for Changes or a Release that are submitted using those features. Periodically, I will have a question or request which requires a response from the assignee or requester of the change. I do this by posting a Note, not adding a comment as I have not yet approved the change request. The problem is, they do not receive an email when the Note is posted. It seems to me that, if I post a Note or ask a question, then the responsible parties should get notified of that dialogue.; much the same way that posting a comment in an Incident, Problem or Task works.