Two years back, I took a personal trip to India on American Airlines ticket. During my return flight, the domestic partner carrier for the leg, Air Sahara, had a "technical problem" and cancelled the flight on 24th April 2004 between Calcutta and Delhi. As I was supposed to fly to Chicago via Delhi and the following flight from Delhi to Chicago was not till next evening, American Airlines agent promised me full refund of cancelled domestic sector ticket as they "couldn't" book me on a different carrier which was operating the same route that evening. Since I had to come back to Chicago as soon as possible due to professional reasons, I had no option to wait till the following day and had to purchase a 347.50 USD ticket to reach Delhi from Calcutta with Indian Airlines (who had the most helpful staff). After I reached Chicago, I immediately sent the ticket to the agent who filed the refund claim.
It has been almost two years now, I am yet to get a penny from American Airlines. I hope they have one more disclaimer in their contract of carriage - "We reserve the right to cheat passengers"