I will be flying Southwest for the first time in a couple of weeks. Last week, with a lot of time to kill in the airport, I checked out the Southwest gates and saw basically everyone already lined up. The boarding process had not yet begun. I asked the gate agent why people line up early if they already have A, B, or C, and he just rolled his eyes and said something to the effect of "I often wonder that myself."

So other than perhaps being the first one on to get an exit row, bulkhead, etc., is there any reason to get in this line? Am I correct in assuming that if I have an "A" boarding pass, I can just stroll up, be one of the last to board in "A", and still get a good (i.e. aisle/window) seat?

I guess a related question is how does one find out if the flight is originating in your city or if it is a through flight?

Thanks.