This morning (updated) afternoon I released a minor update, v4.5.2 (updated) v4.5.3, of Email-Users. This update adds new information on the Dashboard to help the WordPress Admin ensure that the number of users they expect to receive email is correct.
There is a new Dashboard Widget and an updated Settings Page which note how many users will receive each type of email. If no users will receive notifications or mass emails, a warning message will be displayed at the top of the Settings Page.