As on 4.8.2 we do still not have the possibility to hide this button I share my thinking:
In general it would be great if we can disable the unregister by a setting. On my point of view it would be more usefull if we do it in an approach that comes from the Portal.UserRegistration type. If we do not allow any registration (that means that the users will be managed by the administrator by hand or by any synchronizing tool) we should not show the button at.
\admin\Users\users.ascx.vb line 267 we can just add
...AndAlso Not (GetPortalSettings().UserRegistration = PortalRegistrationType.NoRegistration)
full line:
cmdDelete.Visible = Not (User.UserID = PortalSettings.AdministratorId) AndAlso Not (IsUser And User.IsSuperUser) AndAlso Not (GetPortalSettings().UserRegistration = PortalRegistrationType.NoRegistration)
If anybody like to disable it at all just set the visible state to false at all
cmdDelete.Visible = False 'Not (User.UserID = PortalSettins.AdministratorId) AndAlso Not (IsUser And User.IsSuperUser)
Hope this will help someone