Great thread!!!!
Simple, as pax we are freight (albeit self loading!) , and therefore pay by a combination of weight and size. So you get a standard seat width and weight allowance which would correspond to an average person. If you need more than the seat width you pay extra, and why not have solid boundaries between the seats so that those sitting next to an obese person doesnt suffer and the obese one does, seems only fair.
Of course you also pay extra for excess baggage, and why not?
Just imagine an aircraft that got a full load of 20 stone plus pax, it would seriously affect the take off weight calculation!!!
(assume average weight is 12 stone or 168 lbs 200 pax at 280 lbs gives extra weight of 112lbs x 200 22400lbs or 11 tons
)
with the population getting increasingly obese it may soon be necesary for safety to weigh everyone in when checking in...............