Need to include the "(!is_uri_routeable(_req->msg->line.req.uri))" test as part of this condition.  Admitted that always returns true at the moment, but we may make it more discerning in future.  (According to the spec's, you should only consider a URI not routeable if it is a tel URI or a SIP URI with a user=phone parameter - however, few if any UEs seem to set the user=phone parameter, so we don't implement this at the moment.)