Maybe it would cost them that to transport you..if the ticet is so cheap that they are not making a profit putting you in seat..or if they are just breaking even putting you in seat..it would be easier to go with the seat empty..If they are not going to make any money anyway..why put you in thr seat..It just good business to charge extra and see if you will "Bite" and take your moeny,lol @:-)