Change namespace of xml:id

Just in case it doesn't get noticed in the XML Signatures conversation,
I'm recommending that you change xml:id to another namespace
because adding it to the xml namespace does an end-run around
the purpose of a namespace that happens, in this case, to break
something.  Notably, canonicalization.
 
Too bad we didn't think of this for xml:base.
 
Best regards,
John Boyer