"Notify if I'm involved" should trip if I've commented on an issue
Currently it seems notifications are only sent to submitters, assignees, and watchers. However if someone comments on an issue, or has been assigned it previously, it could be assumed they are 'involved' and should get a notification.
One example of this problem is that if someone is assigned an issue, and it then is reassigned to someone else, the original assignee doesn't see any notification of this action.
Perhaps the act of commenting or being assigned should automatically make you a watcher. Then the existing notifications apply unchanged, and you could stop them just by un-watching.