I don't find it very respectful of others to act as if they have an obligation to switch seats with you, as you have a young child and they don't.
Were there any parents on here that who really acted like they'd go all nasty (for real) if somebody refused to change seats for them?
Using your own experiences as an example: What if you went to the airport, and you were separated from your child on the flight, and asked someone to move but they refused? Would you be respectful of their choice to keep their seat? Or would you think"Gee, I am a parent here! They can't possibly need that seat as much as I do?" Or would you stop and consider they may have a need of that seat too? Maybe the one they are sitting with is terrified of flying? Maybe they need an aisle seat because they are clausterphobic?
Well, it was the claustrophobic person before who made assumptions about the mom not REALLY needing to be seated near (within a row in that case) her kids. She didn't pay enough attention to her kids who otherwise didn't exhibit any outward signs of problems on the flight. Might they have had their own issues if they had been 20 rows apart? Stopping and considering goes both ways.
I understand mistakes are made. But what bothers me is the attitude of some that being a parent means their needs trump everyone else's. But be aware that other people may have a need of the seat they are in too. And they don't owe anyone an explanation of why they say "No" if they do when they are asked to trade seats.
I've seen some jokes. I've seen a lot of parents come to this thread to find out more and get a better sense of what they can expect. There have been plenty of reports of fellow SW passengers being friendly and accommodating and no reports of absolutely horrible (final) seating arrangements.
And then I've seen the posts that pre-judge parents, assuming that in real life they'll be rude when they ask (with a light joke?) and nasty if they are refused. I've seen more anticipatory hostility to being asked (at all) on this board than any sense of entitlement on the part of parents.
It's one thing to point out to the folks that are used to Southwest that some AirTran customers have paid extra for seat assignments on top of the baggage fees in order guarantee their particular seat so, if one asks someone to switch seats, it should be done as nicely as possible and without expectation.
It's another to lecture them that they should read all the fine print, call to clarify what "seats will be assigned when you check in 24 hours in advance" means, give up using hard-earned Rapid Rewards points, pay baggage fees and seat assignment fees with AirTran instead of expecting their preferred carrier to offer the service it typically provides, and gripe about how (some) parents have such a ridiculous sense of entitlement. Even of one is absolutely correct about all those things, is that very *nice*? What is this? FlyerTalk?
And that fine print? It doesn't say "You will be assigned seats in as ridiculous an arrangement as possible even though it would be completely feasible provide a better customer experience."
It's NOT unreasonable for a travelling parties to expect, when their seats are assigned at the 24 hour point, that they won't be interleaved with other parties who are all assigned at the same time. There's no good reason for the combined Southwest/AirTran system to do this other than their transitional system integration is poorly done. This seems to be a problem especially with flights booked with points because of the separate confirmation numbers. I had my confirmations linked by Southwest - apparently something in the system supports "linking" but the seat assignment algorithm either does not have access to this information or is coded poorly and ignores it.
AGAIN, this is a temporary issue that Southwest isn't able to deliver the same quality of experience that they've spent decades advertising and delivering. If you've talked to gate agents, particularly the SW employees working the AirTran flights, you'd know that some of them are as confused about how things realistically work at the gate as many of the folks here - who are arguably better informed than a lot of the SW travelling public. And if they're here asking questions, they're becoming more informed.
And, yes, I know that it's tremendously ironic that I am outraged by the new cultural norm of judgy outrage. I'm working on that.
here was my AT through SW experience this morning. I checked in at the 24 hr mark (on the dot) none of our seats were together. But we had one isle seat and infront of that a window seat. My mom was all the way across the isle at the other window. There was a very nice couple who were happy to trade 
I booked our flight on the fly we had been watching fares and one day they dropped thru AirTran via booked thru southwest and SW has free bags and we are a family of 6 so I booked them. Now we don't fly very often at all (my husband does but thru a private jet) anyways I had no idea that I couldn't pick my seats and that they assign them at check in. If it was by the "submit" button then they should have made it bigger because I did not see it till after! Sorry for my mistake. Now that being said we are very easy going people and I would move/trade in heartbeat whether it be for a parent a newly wed an older couple whatever it's not that big of deal for me. My kids are (boys) 15,11,7 and daughter is 2 I do hope that even tho I made a "mistake" booking thru SW I can still sit with my daughter since she is 2 otherwise we will have a huge problem! She would freak! And I really hope my husband can sit with my 7 yr old because he tells stories 
and the whole plane will know everything about us by the time he is done. We do plan on showing up at airport super early so hopefully that will help and if not I do hope we encounter some lovely people who will be willing to help us out. So any suggestions from any parents who have done this before? My 2 yr old has never flown and my 7 yr old hasn't flown since he was 2. Little worried about how to make my 2yr old daughter comfortable. Thanks 
