He would already be in custody, which can be unpleasant enough.
But now the Aussie embassy up there will be working to have him represented and sent home, all expenses paid by we, the taxpayers.
Re squawking 7500 - wouldn't that be a bit excessive unless the guy had made a direct threat? Maybe for disruptive pax we need another code to get the cops to the aircraft in a hurry; batons and tasers at the ready.