Is there really a need for an 'international terminal?'

[MattinCBR]

But surely someone at some stage has to make a record of the person leaving the country. As there isn't any "proper" outbound immigration control, it must fall back on the airline. Whether the airline forgets to remove a piece of cardboard or whether they forget to enter something on their computer has the same effect.

No the swipe of the passport is now just part of the process of checking in to an international flight - and the rate of error would likely be the same as an immi agent not swiping/hitting the right button ie tiny.

As I see it the only downside is for transiting pax - my thought would be if you were to seperate out trans tasman that would leave very few people transiting internationally in australia. There is an oft mentioned plan to turn trans tasman flights into domestic flights in any case, and that would most likely require trans tasman pax to clear immigration off of their substantive international flight (and in Sydney join us all on the bus grrr).