What does it mean to delete a data GUID? If a GUID represents some data that should be later retracted, what methods are in place to help make sure this revocation makes it across the network?
I think in general we assume Data GUIDs are never deleted. If the underlying data gets retracted the Data GUID would simply remove the associated urls to the actual files but remain as a valid Data GUID. I think we could potentially add a flag to the record metadata as well to indicated the revoked status. Maybe this flag should be specified as potential metadata in the DOS spec?