OneWorld rules strongly discourage such practices. Most likely,
JL can manually open-up additional award seats for its own Elite members (as you indicated below).
...
If the special Award Inventory needs to be requested manually, then there is no way to avoid the phone call. While the
KVS Tool can dial the
JL number for you automatically via Skype (when using the main application) or via your Mobile device (when using the
KVS Tool Mobile Companion), it is not currently capable of holding actual conversations with human Agents
...
On conferring with the Diamond member, I gather the message on the JL web site was referring to the Diamond benefit, of the option of using 2x the miles when ordinary seats are not available. Not, explicitly, a reference to additional award seats, at the regular redemption level.
If they do that (or just upgrade without deducting points or miles), apparently they don't admit it publicly.
Sorry for the confusion, thanks for the quick and detailed response.