A Fairfax reporter on the flight says the man appeared intoxicated prior to boarding the flight.
Now, unproven as it is (and it does involve believing a reporter), if that were the case why was he allowed to board in the first place?
A case of hand-ball, perhaps?
In any case, will he be prosecuted for breaking the law - smoking on board at the very least? Simply banning him from flying isn't necessarily enforceable. QF, for example, don't always ask for photo ID (in my experience) and that's only possible anyway if you need to go to a counter at all. On line ticket purchase, self serve bag drop etc. etc. avoids all that.