[XSLT2.0] Error XT1560

I would like to request that whether or not to report this error, be
made implementation dependent in one case.

Namely, when the clash occurs for a named output definition that is
not referenced by an xsl:result-document.
As far as I can tell, this must be harmless, and checking for the
error would be awkward for my implementation.
-- 
Colin Paul Adams
Preston Lancashire