cross-book olinks in epub

hi,
I'm using xsltproc with the 1.76.1 epub/docbook.xsl stylesheets. When
creating a standalone epub doc, I get real hyperlinks for
cross-document links.

For example, see this page from the DocBook XSL Guide:
http://www.sagehill.net/docbookxsl/Olinking.html

Suppose you create an epub of the userguide; I believe it should not
contain active hyperlinks to the admin guide.
I think that such cross-document references should resolve as text-only.
That is, a hyperlink that goes to an external docset should not be
created for epub.

That is just my opinion, I haven't read the official spec. But it
seems unusable for an epub to retain relative links to an external
document.
Does that make sense? Am I misunderstanding?

thanks,
--Tim Arnold