I am so sorry you had to deal with that. I had a bad experience last year. Normally, the flight attendant very discretely hands me a seat belt extender, and that is the end of it. I generally fly about once a year, and I have weighed the same, plus or minus ten pounds for a long time. (Haven't had the surgery yet) The woman at the Southwest gate came charging down the ramp into the plane. I was in the process of putting on my seat belt, and she kneeled on the seat in front of me, facing my husband and I. She said that I couldn't fit in the seat with the arm rest down. i said I could, wait and look. She said in a nasty voice, "Not comfortably!" I had just flown a week before on two planes with Southwest. My husband was sitting right next to me, so there wouldn't have been another customer complaining. She told me she had to put a seat between me and the other passenger, had a printed "reserved" ticket that I had to place between us, and told me that I was now in the computer as a passenger who requires two seats. She was not discreet. How humiliating! I am flying to Chicago next week on American. I hope there isn't another incident. I've never had that problem before.
I was traveling with my husband who had a stroke six month earlier, and has stage four cancer, so I didn't get her badge number.