Domino 9 introduced Protected Groups like LocalDomainAdmins/Domains, but groups still can be deleted with CTRL-X or CUT menu. only few users use Actions, busy people use shortcuts, as result it is possible to workaround this protection.
I also wish for system objects like LDAP user or Administrator there is a property SYSTEM object, and FORM looks a bit different, so for user it looks different as well. and when user modified additional Message box appears, "Hey this is system object, are you sure what you are doing?".