LC Comment: Multiple reply relationships

The rules for formulating a reply in section 3.2 state that "a new pair 
of IRIs is /added /to this value as follows ..." (emphasis added).  We 
have recently clarified (in LC15) that there should only be one reply 
relation in a compliant message.  A compliant processor is required to 
produce a compliant message in response to a compliant request.

However, it is possible for a request also to be a reply, particularly 
outside the context of the usual WSDL MEPs.  In this case, the request 
message may still be compliant, but if it is, the responder is obligated 
to produce a non-compliant message by adding a reply relation to a 
message that already has one.

This could be resolved either by prohibiting request messages to have 
reply relations or by allowing (but discouraging) multiple reply 
relations in compliant messages.