Scenario:
An administrator may have to delete a user's auto-generated holiday booking if the user has to work on that holiday. The Time Off Booking is deleted but no email is triggered to the User.

Cause:
An email will not be triggered when auto-generated holiday booking's are deleted, since these bookings are system-approved. An email is always triggered if a user is involved i.e. either a user books it or an approver, approves it. In this case neither the user nor the approver is involved as the TimeOff is booked and approved by the system. Hence no email is triggered.