I flew Southwest this past weekend. I am large, but I fit into one seat. I had never heard of this policy before--I got on my plane, had no problems, until we changed planes in Dallas. While I was waiting at the gate, a SW employee came over and asked if I was comfortable in one seat--I had no earthly idea what she was talking about--I told her I was. She kept saying, "this is for your safety and comfort." She kept asking, over and over, about the armrests, she left for a minute, came back and said 'they' wanted me to pre-board, for my safety and comfort. Being embarrassed publicly has never done much for either my safety or comfort. I really didn't know that was going on until she said the flight was overbooked and if I couldn't fit comfortably in one seat, I would have to get off the plane or buy another ticket. (buy another ticket when it's overbooked???) I argued that I had no problem on the flight I had just left--she didn't seem to know this was a second-leg (so much for security) and asked me several times if there were issues on the first flight. She finally let it drop. I continued my flight, sad, depressed and my weekend trip was overshadowed by the dread of a possible repeat experience. (didn't happen). It seemed to me the policy is if you sell too many tickets,kick the fat person off the plane. I don't think I 'spill' onto others, but if I do, I was seated next to my companion, who really wouldn't mind. I've never complained about tall people whose legs move over into my space or people with bad breath or body odor. I haven't even complained about the cheap, sickening perfume of the nice lady behind me--I knew in the grand scheme of things, it wasn't that important. To those who would be offended if I sat by you, if for some reason I didn't want to be by you, I would never want to hurt your feelings by telling you so or calling you names. Just wasn't the way I was raised.
Ironically, when we landed at the Austin-Bergstrom Airport, I looked up and saw we had deplaned at the Barbara Jordan Terminal. She was a great lady in every since of the word. I would have been honored to have been able to be seated next to her on a plane and if she needed some of my space, she would have been welcome to it. But how horrid it would have been if she had been treated as I was.