What about someone really tall? Someone 6'8" weighing 16 stone would then be charged more...
Yes, but the average person isnt 6'8" I have had a really tall guy behind me before on the plane and his knees were sticking in the back of my seat. Almost as annoying as a fat person spilling into my seat that was next to me
Fat people pay extra for 2 seats
Tall people pay extra for seats with more legroom
Thinking about it my idea would be that fair on others on the plane. E.g. you get a 30stone guy who is rich and just pay for all his excess weight...back to the drawing board