I just dealt with this type of thing whilst flying Sterling Airlines (the old Maersk) from London to Copenhagen.

They charge you if you want to sit in the exit row, in the front, in the back, at a window, on the aisle, or with your friend!! Completely ridiculous but very Scandinavian in that special "if you want something specific you better be ready to pay for it" kind of way. Check it out if you fancy it:

http://www.sterlingticket.com/home/d...enskeplads.htm