when i park my car, the garage charges me double. when i ship an oversized package, i pay for the extra size. your carryon 25", you pay extra. you need two seats, buy 2 seats. you weigh 500 llbs, you buy 3 or 4 seats.
i get upset when one of those 300+lb porkers, with a fat wallet seem to think that since life dealt him a round profile that he can take 20% of my seat.