If she wants to stand in place and wait so badly then she can ask someone in front or behind her to remember her place in line and let her back in later (most people are willing to agree to this if asked politely), then she can stand off to the side until her spot gets to the front, and go back to where she was once it’s her turn, then everyone gets what they want.

We can all do that! Just remember what order we were in and stand off to the side until our turn in order comes up. Though, to make sure no one gets in other's way when it's our turn, we should stand off to the side in order of who's place in line is first. Then we can all just stand off out of the way, all queued up!

Wait... what's that? You're saying I just made a whole other line in a different spot in a less efficient layout and not the area selected by the airport as closest to our destination? And this person's "system" only works because she's the only one doing it and she thinks that she's figured out a cheat-code for life, but is actually an asshole?

Society would break down if everyone just did the thing that was best just for them with no credence given to anyone else. The only reason she's able to get away with doing this kind of thing is because everyone else cares more about moving on with their life and the established systems moving forward rather than grinding them to a halt to get her on board. It doesn't make her more logical. It makes her more selfish.