I think that actually perfectly summarises the rule - if direct flights are available (even if availability is gone), then creating a stop over at some other point would be in breach of the published rules. For years DC have been very lax in enforcing that - but now it looks like we are starting to see them tightening up. It does ultimately mean much less award availability for us - but all good things come to an end (and no one can deny they have got more from their DC miles than any other FFP around).