Quite amusing, but perhaps a little harsh on the "fatties". I have to admit that I have no sympathy with them; we all have our problems, and having lived and worked in Africa for 2 years, there was a dearth of fatsos there (plenty of AIDS victims though).
As a skinny one, I would love that we all paid by weight. I could probably carry loads more luggage, whilst fatties would be reduced to a toothbrush. I think it's the only fair way; step on to the scales with all your luggage, and get charged accordingly.
If people can't control their behaviour, whatever it is, I don't see why the rest of us should suffer, or pay for it.