I hope I'm helping you. Here's what I know in response to what you asked/mentioned in the quoted post. This may be long, but I'll try to be as clear as possible.
Yes, Southwest has good rates especially once you factor in 2 free bags!
I love that and it's why we decided to do Southwest with our girls for this trip.
There are no assigned seats, the seating is considered open seating. As you board, you get your choice of seats. You can sit where ever you want, first come, first serve.
Please know that buying EBCI does not guarantee that you will all have seats together, all it does is guarantee that you are checked-in early. Because you are checked in early, you are likely to be given a lower boarding number, which in turn increases your chances of sitting together since you will be some of the first people on the plane.
Side note here: My personal plan of attack is to head right to the back of the plane because it's the least desired spot. I mean, really, you are all going to the same place does row 1 or 30 really matter THAT much? Well, maybe it does if you have a business meeting or something, but a vacation not really. Anywho, back on topic...
As far as your son ending up alone, I have seen reports of 2 things happening in this situation...
1 - Some people (most I would like to assume) would be willing to move their seat so he can be with his parents, but I have read that the attendants do not force anyone to move. I personally, would not like to be seated next to a little crumb-cruncher that I do not know for hours, especially when their parents are in a different row. I'm willing to bet a lot of adults feel that way too.
2 - On the other hand I have read where the pilot won't move if the child isn't with their parents. In this case they are basically forcing people to move, which is the complete opposite of what I explained in the point above.
In both of these cases, I am sure that the age of the child plays a factor. A 4 year old child sitting alone is quite different than a 14 year old.
And then, there are some other situations where the seating game becomes even more of a game...
1 - If the flight is operated by AirTran but you purchased through Southwest's site. This is an issue because the people who are buying the same flight but through AirTran's site are paying a fee to pick their seats. If this happens then you have some people who already have assigned seats and then ones that don't have them. The ones that don't have assigned seats then have to fill in around those who do. I say this...you're wanting a flight operated by AirTran then book with AirTran, if you're wanting a flight operated by Southwest then book on Southwest's site.
2 - The second thing to cause issues with seating is if the plane is originating from another city and some of those passengers aren't getting off. Then, once you board, you will again be filling up around those who already are seated.
I hope that all was clear enough to understand.
