The LC bibframe team discussed this at length this morning.
There were only about four messages at the time and now there are now many more, too many to keep up with it all. Among those early messages there seemed to be only this use case:
<http://example.org/2335409#Work> a bf:Text, bf:Work ;
(Nevermind what constitutes sameness - whatever institution A considers it to be. Could be matched based on author and title for example.)
We don’t think this is an appropriate use of bf:identifiedBy. http://worldcat.org/entity/work/id/638612 doesn't identify http://example.org/2335409#Work. Rather, the assertion is that they are the same resource.
We recognize that there is a need to make such an assertion, that bibframe currently does not provide one, and we will investigate this further.
Still, bibframe does not preclude declaring that a particular URI is an identifier for a particular resource (although we would still welcome a use case). As has been suggested, it should be quoted (a string) rather than a resource. bf:identifiedBy is intended for string identifiers, not for identifiers that are themselves linked data resources.
a xs:anyURI ;
rdf:value “http://example.org/identifierA” ]