And this does happen. Once we had pre-boarding because our one year old was handicapped. Because my husband needed to put his car seat in place while I took care of our son. The whole family (me, DH and 3 sons) had to line up to pre-board. Actually we checked with the agent at the gate and she understood completely until.....B26 and B27 started freaking out. They started screaming that our older kids could hold the baby and the bags. And I should go to the back of the line. They created such a scene the gate agent was unable to control them. She asked if I'd mind taking my place in line. No problem, I was A4. They got worse. They wanted me in back of the line. I did just for the sake of peace (I was not worried about where I was going to sit). Unfortunately, the baby had a fit when he got on the plane without me and broke out of his brace. The older kids were scared because they could not control him. Take off was delayed by a couple of minutes because we had to get his brace back on and it took time to get him situated in the seat (hence the pre-boarding) and he cried in pain the whole flight home. I hope B26 and B27 were satisfied.

So, yes I guess OP should be prepared for B26 and B27.
I feel so bad for you guys!
But the boarding system must have been very different than the airports I've used...B is never even lined up at the time of pre-boarding (not family boarding but true pre-boarding). B is just sittin' down, cooling their heels until A is already going. Seattle, San Diego being the two airports I use for SW.
And why did you give in to the B passengers when the employees were OK with you? Please don't do that in the future...


Especially when you are A4, which means you were either just about first on the computer or you paid extra (depending on when this happened)...
I personally think this is a ridiculous post with some of the answers I have seen. Anyone who has a problem with a 3 year old boarding with their mom NO MATTER what her number is nuts. That kid is going on my hip and I am walking to the agent with both passes!
And for that matter. Shame on Southwest for not making sure that families booked on the same reservation receive boarding all in a row. We have had it happen that we click on our one reservation and the numbers dont line up. Whats with that? Fix it and you won't have families panicking that they can't sit together.
I disagree with the first paragraph. As I mentioned, I went to the second number, because I felt it was simply polite of me. The lady in between our numbers was just as polite; would she have been if I had 5 children who all had later boarding numbers? Doubt it! So I did what I firmly feel is the right thing, and would have been totally fine if she had wanted to keep it that way.
Eh...their system is fair, IMO, because it goes with the first info received. So the packet of info received about MY ticket was received, then the lady in between, then my son's...it's fair. IMO.
I also enjoy the camaradarie between passengers as you're figuring out where you are in line! Showing boarding slips, asking who is what number...it's good fun, IMO. I don't have a single problem showing my number to anyone.
But I don't think any of this is worth worrying about for the OP. Just go to the second number and wait there. That's the most polite way. If you want to take the first number and bring the kidlet, do that...not quite as polite, and even more passengers between adult/child and other adult, more passengers who might decide that their life's dream is to sit in the same row as adult/child (as is their right with SW boarding!), but you can try.
I just...wouldn't *worry* about any of this.
Maybe it's just me as I haven't seen this said yet. But, IMO, if I check in myself, dh and my kids and I don't want my kids to stand in line and walk-on alone, I will have dh and/or I go to their position - or, more accurately, to the least common denominator. I would never assume it's proper or fair for me to bring a person ahead in line with me. I would, instead - go back in line with him/her to a position AFTER my boarding number.
It isn't fair to A25 if you now have two A24's....Now, I agree - no big deal if it is just one child. But what if everyone from A1 to A23 wanted to do the same thing?? I know, extreme case, but what gives me the right to take up two spots in line?
Anyway, to be fair - I would just board at the position with your child. Or, as a pp suggested, you board first and have dh with the child at the later position so that you can get in and get a row and then LIKELY no one else will sit in that row with you since they will be boarding shortly after.
Also, on my SW flight - the SW gate agents INSTRUCTED US to show each other our boarding number as to get in the proper order. I'm not sure what I would have done if the people around me didn't?? Maybe just step in front of them assuming they had a higher number than me since they didn't want to share. I think that's pretty rude not to show anyone. If my dd's kindergarten class was instructed to get in order after having been given out numbers 1 - 20 I would expect them to do so by asking/showing each other their numbers - not much of a difference here, IMO.