We use redmine extensively for IT support requests.
Often users unfamiliar with redmine will make comments on a ticket that is assigned to themselves like "Yeah, go ahead and do that - sounds good."
And expect us to know that they have made a comment.
We have a very high volume of tickets, so we only subscribe to updates for tickets assigned to us.
It would be useful if when a user makes a comment on a ticket and does not assign it back to another user that they get an email warning like:
"Redmine notification regarding #99999: You have submitted a comment on a ticket assigned to yourself. No other staff member has been notified. Please assign this ticket to another user or add a watcher if you expect others to be notified of your update".