There's a documentary on Netflix, I think it's called "Speed" or something because it's about fast stuff, had an episode about doing Monte Carlo simulations of plane embark / disembark sequences that were optimal. They came up with optimal boarding processes but it required individual seat assignments which was a problem for kids (not to mention a ton of explaining). I forget if Southwest's semi-randomized approach was the next best, or boarding groups - I think it was randomized.