[trentnelson]

> Actually, I think that this may not have even constituted unlawful presence; since the author was not yet technically in the country until exiting the airport, she was essentially just turned away at the border.

Yup, it's officially referred to as "Denied Entry". You never enter the country, officially.

> (with a brief detention for practical reasons)

If there was a return flight 4 hours later, they would have been put on that. The fact that the timing didn't line up was unfortunate, but as you say, it's practical.