rdf:nodeID and external entities?

http://www.w3.org/TR/rdf-syntax-grammar/#section-Syntax-blank-nodes

Spec does not seem to mention the impact that expansion of external
entities would have on rdf:nodeID.  For example, if I have:

File1.xml
<rdf:Description rdf:nodeID="1">
&extern;
</rdf:Description>

File2.xml
<rdf:Description rdf:nodeID="1">
....
</rdf:Description>

I would expect that the two would _not_ resolve to the same blank node,
even if &extern; was pointing to File2.xml.  In other words, I expected
the spec to say something like:

"values for rdf:nodeID are evaluated with respect to the baseURI
property of their containing element"