I was seated in the bulkhead exit row (row 10, best Y seat on a 333) on a recent NW TATL flight. The gentleman sitting next to me required an extender. After the flight door had closed our purser politely informed him that he would not be able to use that seat and apologized for not notifying him sooner. She then escorted him to his new seat, in WBC. I don't think he minded.