Right, I mostly get that. I have literally never seen anyone use a computer at airport security. As such, the joke falls rather flat. Would be better on a story about using emacs on your phone?
Some people print their tickets at home. That's what I assumed they meant.
I should have also said I meant my quip mostly in jest, as well. I don't actually question why they would be doing something I know they aren't actually ever doing. :D