Should Obese Passengers Pay more?

This picture has been posted on the web but it is not an uncommon site. While it appears to me that the passenger is partially resting on the outer armrest, he is still large and will take up some of the seat of the passenger sitting next to him or hang into the aisle. Now, all armrests are to be down before take off and landing so the other question is can he put down the armrest? If not is this a safety risk not only for himself but for other passengers? You be the judge!