Instead of deleting users, we inactivate them.
As a non-staff user, I can make my profile inactive in KARL. Doing so will prevent future login for my user profile, prevent me from receiving email alerts, prevent me from sending email into KARL, and prevent my profile from showing anywhere in the system (including search, people directory, and community membership listing) with the exception of when viewing content I have authored in which case the link to my profile still works for historical reference. Administrators can also perform this same functionality on any non-staff user.
The backlog description has sufficient detail.