I've always thought this practice at Changi to be particularly baffling. It's to do with the process that Singapore residents and citizens (who are able to use the automated passport machines at immigration at Changi) have to go through at immigration.

After checking in for your flight, when you enter through the immigration doors, your passport is first checked by the airport security.

Then you walk less than 10 feet away to the automated machine, scan your passport, put your thumb print, and if successful the machine door opens and bids you bon voyage.

But as soon as you leave the machine, barely 3 feet away, a second airport security person stands there and insists on verifying your passport and boarding pass - again!

I'm baffled... why would a country as efficient as Singapore do this? As if I can morph into a different person between the first security person and the second, who literally are about 15 feet apart from each other? What's the purpose of the first person's manual checking of my identity, followed by electronic and biometric verification of my identity, only to be followed by yet another manual verification of my identity... literally steps from one another?

I have long thought of this as a waste of government resources... but happy to be educated by those who justifiably think otherwise.