On the subject of status codes for "does not support"

Following up further with Mike Beach's question about how a responder might
indicate that it doesn't support a particular SAML feature, there's also a
status code in the spec since prior to last call:

urn:oasis:names:tc:SAML:2.0:status:RequestUnsupported

Again, I don't know how a requester would even know where to send such a
request, but if it just fired one off to an endpoint it knew about that
supported some other profile, this would be one way of responding.

-- Scott