They're c***s. I had a rant about BA in the New York thread recently when they changed the time of a flight between Toronto and New York, meaning I missed most of a day in New York last month. My options I was told were pay £300 to get on a flight 10 minutes later than our original, or stick with the new flight time.
I sourced a flight on Air Canada from Toronto that morning for about £150 for the 2 of us, so told BA i wouldn't be getting on that leg of the journey. I was then warned that if i skipped the Toronto to NY flight, my homeward travel to Glasgow via Heathrow later that week would automatically be cancelled. The admin fee to take me off the flight so happened to also be £300. I made a point of telling them they were robbing c***s.