Okay, what is the logic of not selling someone two seats? Knowing that they are 400+ lbs, and cannot comfortably sit in one seat, United still will not sell the extra seat?

As a plump person myself, NAAFA has some good readings on how to travel with a heafty figure. The main recomendation, if you can afford it, is to book two seats adjoining. Sounds like united is against fat people! Wait til NAAFa hears about this