After a release has moved to a status of 'Committed' for example, we would like for any watchers (or other subscription) of the release to have an email or view that lists any changes with features moving in and out of the release. As a nice to have, any features that have changed in rank could also be reported this way.
Currently, watchers on releases will receive emails whenever any changes occur for that release. One workaround would be to remove and add watchers until you are ready to send email notifications to users (based on changes)
At this time, we do not have plans to use the release status field as a trigger for email notifications, based on current priorities and community feedback. We hope you can understand.