When I first started work in the late 1960s I took a job as a travel agent. One of my clients went to Saudi Arabia on business and when he came back he described how he had spent three days trying to fly between 2 cities. On days 1 and 2 he had checked in, been given a boarding pass and headed to the gate and then across the tarmac to the plane only to find every seat taken.
On day three he decided he wasn't going to be left behind. He made sure he checked in early, was first on to the tarmac and, if not first on the plane (he was a tad large!) he certainly wasn't last and he flew (he claimed there were standing passengers and I saw no reason to doubt him).
Queuing? Orderly behaviour? Optional in many places.