The fact that the flight was not overbooked may seem trivial, or pedantic, but there is very important legal distinction to be made. There may not be a difference in how an airline (typically) responds when it needs additional seats, such as asking for volunteers who wish to give up their seat for a voucher or cash. But there is a legal difference between bumping a passenger in the instance of overselling a flight versus bumping a passenger to give priority to another passenger. Any thoughtful person can see the problem that arises if an airline were allowed to...