Хорошая иллюстрация к понятию commitment.

[cass1an]

"The reason that airlines don’t automatically upgrade economy class passengers to empty seats at the front is not the fear of annoying passengers who have paid full fare.  The reason is that airlines don’t want people who might be willing to pay for extra legroom to book the cheaper seats in the hope they’ll often get a business class seat for free anyway.  So to make sure that businesses go on buying premium seats, the airline does not allow economy class passengers to move in to empty business class seats once the plane doors have closed, even though there would be no marginal cost to these seats being used. This rule therefore reduces overall passenger welfare (because people could fly in more comfort at no additional cost to society as a whole), but is maintained by airlines to protect their ability to charge higher prices to passengers with a higher willingness to pay."

http://www.owen.org/blog/8493
вся статья хорошая про это же.