I used to always fly southwest out of Burbank, and they exit from the front and back. I would always board late and go to the back, and be the first one out. I got pissed when they started telling people during boarding about how they exit at our destination, and more people sat in back.
Southwest still lets everyone choose their seat.... you get a place in line based on when you check in, and when you get on the plane you pick any seat.