No, if you do not like having your "space" being taken up by a fat person, YOU get up and move. Not them, YOU! So, if I pay for a seat on a plane and fatty sits down next to me, somehow he/she is entitled to part of MY seat?!?!
Talk about your all-time twisted logic!
You seem to be under a misapprehension of the facts. You're NOT paying for a seat. The ticket is a contract between you and the airline to take to from point A to point B with an agreed-upon level of service. . .