Hi Simon,
You are doing it correctly. But not sure why the emails are still getting triggered !!. Can you stop the dispatcher and re-start them. I also recommend to regenerate the dispatcher scripts before restarting them to see if it can fix the issue.
But to make it more clear for you, below is the explanation on how it works.
In the provisioning framework, either it is provisioning/de-provisioning/modify, after successful completion of the task, there is a notification task triggered. Please refer to the below task for provisioning.
So, that notification pass will check against the repository constant ENABLED_FOR of the repository and verifies that is the notification enabled for the trigger ? using the script sap_core_check Notification.
If the notification is enabled for the corresponding task, then the script sap_triggernotification will set the attribute MX_TRIGGER_NOTIFICATION with the trigger . In this case ' Create User " followed by which the notification will be triggered.
~ Krishna.