What a scheme.  If the airline sold you a seat, whatever the price, or conditions, its now your seat.  For sure, if they find themselves in an overbooked state, or onie like this, where they suddenly have to fit in four crew to make another flight, they could easily enough up the offers until they found four passenger willing to rebook.  Everybody has a price.    The strategy now in force seems like something out of the pages of the Aeroflot of old.