Removing a user may leave segments owned by that user
When you create a new user, depending on which protocol is used to create
it, it will be assigned a newly created Segment as its default segment,
and ownership of this segment is set to the new user.
If you remove a user from AllUsers, the segment/s owned by this user are
not modified, and continue to reference the removed user. This will prevent
this user and objects created by this user from being garbage collected.
The User Administration tools in GBS transfer ownership of Segments to
the user that is performing the operation.