SRU mime type: +xml or not?

["Ray Denenberg, Library of Congress" <rden@loc.gov>]

'application/sru' or 'application/sru+xml'?

http://www.rfc-editor.org/rfc/rfc3023.txt  says:

 When a new media type is introduced for an XML-based format, the name
   of the media type SHOULD end with '+xml'.  This convention will allow
   applications that can process XML generically to detect that the MIME
   entity is supposed to be an XML document, verify this assumption by
   invoking some XML processor, and then process the XML document
   accordingly.

And later:

XML generic processing is not always appropriate for XML-based media
   types.  For example, authors of some such media types may wish that
   the types remain entirely opaque except to applications that are
   specifically designed to deal with that media type.  By NOT following
   the naming convention '+xml', such media types can avoid XML-generic
   processing.

So .... should a document of SRU type remain opaque except to applications 
that are designed to deal with it? Or, if a non-SRU-aware application tries 
to process an SRU response (for whatever reason) should we make it easier 
for that application to be able to do "XML-generic processing" even though 
there is little chance that it can do anything useful with it?

--Ray



--Ray