Email notifications for announcements silently fail if the user adding the announcement has an empty email address, e.g.:
Login as admin and check that admin has no email address
Go to a site with an announcements tool
Add announcement, selecting Email Notification: High - All participants
The announcement is added, but no email notification is sent. No error message is displayed to the user, and no warnings or errors are logged in catalina.out.
The tool should display a warning to the user, e.g. "You have selected email notification for this announcements, but you have not set an email address for your account. No email notifications will be sent."