Most people who have flown are familiar with the Southwest Airlines “cattle call”. For those who don’t know what it is, I will give a quick explanation.
Southwest doesn’t give assigned seats for their flights, rather they issue a letter to you, A B or C. When you get to the gate, they simply say “group A get on” and that is what happens. Those who check in earlier receive the preferential section and therefore the best shot at getting those invaluable exit row seats. The problem with this was that people would begin lining up hours in advance of the flight. They had separate lines for the A, B and C sections. If you were in the rear of the section A people, there is no shot at the more valuable seats, but at least you could still get an aisle or window.