I always buy Early Bird. One time, though, I bought and still got a high “B”.
The ticket collector let the jerks with the higher # in the boarding segment on ahead of the lower # (i.e. # 38 got on before 35). It didn’t really matter in the big scheme of things, but it was rude. I don’t think she even looked at the pass- just scanned it and took the paper. I tend to ask people what their # is so I can stand in the right place, and it usually gets people to line up correctly,
I get annoyed with that, too, @jym626 - though my husband frequently does the same thing. I won’t let him do it when we travel together.
A slight digression for folks who live in a city with good SWA service and will be doing college visits with their kid(s). It takes 110k points to earn a Companion Pass (your companion flies free with you). SWA offers multiple types of credit cards, each of which includes a 50k point bonus once you spend 2k. If you get 2 of their credit cards that’s 100k points, so earn another 10k points (either through spending or flying) and voila, Companion Pass.
I somehow managed to accidentally earn a pass last year via one of their cards and used it for several trips to California with D to check out colleges.
When I make my reservations these days, I schedule the check-in on my iCalendar with an alert five minutes before 24-hour check-in. In that ‘event’ I’ve scheduled, I also type in my confirmation number, so I’m ready to roll when that 24-hour time period comes no matter where I am. If it’s more than a two-hour flight, I will do EB. But even without it, I don’t think I’ve ever gotten a C group when I’ve checked in at 24 hours. If you’re A or B, you’re practically golden with an aisle or window seat. The issue becomes if there are two or more people traveling together that insist on sitting together.
I am also lucky in that we fly in/out of Midway, which is a hub, and almost always have direct flights to where we most frequently travel so we don’t have to really worry about connections.
On a recent flight we were A group and boarded, and noticed that in the row behind us was a woman chatting with a flight attendant. Turned out they were saving the row for the family-- with a baby and a toddler. Sigh…
@intparent Your post #39 reminds me of the Doritos commercial. “There is an art to it. . It doesn’t always work. But usually it does.”
If it’s available when I book, I do BC on Southwest, and if not, early bird check-in, again if available, because I like an aisle seat in the front of the plane (have some anxiety during take-off, and being in the front helps). So, I always pay more for my ticket. It really irks me to see people saving a whole row on the plane - I can understand the next seat over, but the whole row is really nervy. On almost every Southeast gate there seems to be a large family group with a four or five year old who doesn’t know the drill and thinks they’re going to get to board before everyone else. They always get sent back to their boarding position - Southwest is good about only allowing those on first who have been issued early boarding passes.
I say something to people who are saving seats, and have even taken the “saved” seat. Only when I intended to sleep the whole flight, though. 
And yes, @doschicos, that is it – I will have to add flossing to my repertoire.
It sometimes good to board in the B group - all the babies and toddlers have boarded already and you can choose your seat accordingly.