I flew Southwest as a Pooh size traveller in October, on my trip down to WDW. I bought the second seat. I had three flight segments to Orlando and two home. On four of those segments, the plane was full and I had people giving me dirty looks because of my empty second seat. Because of the sold out flights, I wasn't able to get a refund for the second seat, but that's okay. I bought it for my comfort, because I was concerned about not fitting, and also because I was concerned about someone complaining and my being asked to leave the plane if someone complained.
All told, while it's expensive, it was worth it. Checking in was difficult at Midway, but because the agent didn't know how to do it and had to call for help. Checking in at Orlando was very easy. At one point on the last segment home, another passenger pitched a fit that I wasn't letting them sit next to me (despite the clearly visible reserved sign on the second seat) and got the FA. The FA explained to the other passenger that I'd paid for the seat and had been on the plane since it originated in Orlando and she wasn't going to make me move.
Some people tell me that I'm not "big enough" to need two seats, but I tried to sit with the armrest down because a friend on my PTR had asked me to see how I'd fit, and I was extremely uncomfortable with the armrest down. It was worth it to me to buy the second seat. I'm going to DLR in May for my birthday, so I'll be buying two seats on Southwest when I get my tax return, and will likely be flying Southwest when I go back to WDW in December.
But I do agree that the people who complain about plus size passengers being so big and then complain about them
following the rules and buying two seats need to stop complaining or find something else to complain about. I followed the rules Southwest had laid out, and still people complained, even though I knew they wouldn't have wanted to sit next to me anyway.
But I can't tell you how many people walked right past the third seat in the row, not realizing they would've had a little more room
