This issue is essentially closed by the modified encapsulation rules in the -05
version. The 'normal' encapsulation described in 5.3.1 is always available for
Data messages in this case (i.e. datagram mode for all routing methods).

The current draft is based on the model that where messages have to be sent to a
particular node they will be sent over a messaging association. However, it
doesn't guarantee that such a messaging association will always exist. In
particular, a node may have downstream routing state towards a specific peer
without a messaging association. However, in that case there is no downstream
message encapsulation which will deliver the message correctly to the specific
downstream peer.

(This is probably another argument for decoupling the message encapsulation from
the message direction.)