That hour or so you spend waiting for your flight could be better used. Having dashed to the airport, made your way through check-in, past security and beyond customs, passengers are left to twiddle their thumbs for an hour so while bags are stacked and the plane is prepared.
And then, upon landing at our destination, we drag our sorry selves through another customs queue.
Depending on the airport, the wait for customs can be horrendous. Particularly after a stinking great long-haul flight in unwashed clothes, breathing the same recycled air, rubbing your sore back as you approach the customs official... "You've filled out the form incorrectly sir, go to the back of the line."
The Americans are on to a good thing with border pre-clearance. After check-in at some airports flying into the US, you go through US customs - wait for it - before boarding the plane.
At this stage the service is available to passengers from most major Canadian airports going into the States, from some in the Caribbean, two in Ireland and one in the United Arab Emirates.
It's good for passengers as it makes use of dead time before departure and saves time upon arrival. It's good for the airlines as they can land at smaller airports that generally host domestic flights, giving them more options in spreading the load of their fleet.
Who would be against the idea? Airports perhaps - the time you spend filling in your forms at your departure gate is time you're not spending buying food drink and duty free to keep the airport's profits up. On arrival we tend to spend less, eager as we all are to get the hell out of the airport.
Restrictions on where pre-cleared passengers can go in the departure area could limit opportunities for revenue.
Our own special relationship with Australia sees transtasman fliers whizzing through SmartGate, provided they have the right kind of passport.
SmartGate visitors between the two countries arrive with a Special Category Visa, meaning they can stay and work as long as they remain of good character.
In the spirit of Anzac, I won't make the obvious joke about Australians and good character.