> “The booking systems would have to be programmed and supplemented accordingly in order to enable the ‘pay as you check-in’ solution and make it the standard,” Carnier said.

Spoken like a true software engineer.

From my experience with people booking and taking appointments I can assure you, the airlines would be out of business within a month. If there is no upfront payment people just won't show up. Nobody cares anymore. The average person is too unreliable these days.