It isn't the first diversion either Keg, Fiji, Kuala Lumpur, Dubai and Noumea have already been used for unscheduled stops.
OQA did a few training flights into Adelaide in 2008, so it had been done before. As has already been mentioned this is a non event.
Except for the early risers in Adelaide who might have had a double take at seeing a dugong at their airfield.