The strategy of trying to maximize revenue has pitfalls when the flight occupancy rate falls significantly. Of course, if revenue levels can be maintained while carrying fewer passengers, that much is good, but invariably someone in the bean counter department gets concerned about empty seats and the remaining inventory goes on sale. Under the "butts in seats" rule, selling a cheap fare is better than carrying "air" in what becomes a perishable commodity - the empty seat. The challenge is to be ready to react when the sale happens. Most passengers are not that diligent, or obsessive, once tickets are purchased, they are done.