In reply to Michael O'Neil.

You nailed it, Michael! (Or can I say "Neiled it"? :) ) If you attempt to assign an existing Library Name to a new Library in SAS Management Console, it will display an Error pop-up window stating "A library named 'SomeName' is already assigned to the server 'SASApp'." preventing the new library creation. I agree that something similar could be done with the librefs too.