I flew back Business from Malaysia a few years ago. As passengers were still boarding a very large lady came through into Club Class followed by two harased CC. She pointed to some empty seats and started demanding that she be given one of them. Basically, she stated that she was too fat for an economy seat, especially as it was a 14 hour flight to London. Therefore, she announced, it was the Airlines responsibility to upgrade her. Luckily, they refused.
I was annoyed that this rather nasty individual thought it her God given right to be treated as a special case due to her size. She purchased an economy ticket and that is where she should sit. She tried to make it the airlines problem and even tried to intimidate the CC with threats of 'letters to management'. Her size is her business and her responsibility.
I get annoyed when I see morbidly obese people shoe horning themselves into seats, especially ones near me because of the safety implications in an Emergency.
I for one, hope we do not address this problem by giving them the legal right to sue if we dare to mention their excess girth and the problems it causes.