Interoperability and Servicedesk
The service desk of the implementer should be able to help the end-user beyond the boundaries of the own implementation. If the root cause of the incident is found or can only be serviced in a third party's implementation, then one of the service desk of that third party or the writer of the specification should be informed. Otherwise the end-user reporting the interoperability incident will not be serviced and a possibly underlying problem will not be solved.