I think the airlines just enjoy seeing how far they can push the public. See also the posting below.
American AAdvantage has changed its fees to book an award ticket within 21 days of departure. Previously, the fee to book an award flight between seven and 20 days prior to departure was $50 and the fee to book an award within six days was $100. As of Aug. 25, 2011, the airline will charge a $75 fee for all award flights issued 20 days to two hours prior to departure. Members who book flights a week out are now paying $25 less and members who book two to three weeks out are paying $25 more.
The fee for additional tickets booked at the same time from the same account has also increased from $25 to $75. So if an AAdvantage member books three tickets two weeks prior to departure, the close-in booking fee will be $225 total compared to the $100 that would have been charged under the old fee schedule.