Just to add to the discussion, in contrast to the BA approach I had a very positive experience with US a few months back. I was flying EWR-PHL-xxx on a cheap ticket, departing 1829 (the US$150 change fee was more than the cost of the original ticket). The combination of congestion, weather and usual US East Coast short-haul mess meant that my 1829 departure was delayed just enough to make it likely (albeit not certain) I would misconnect in PHL. There was a later same-day flight to my final destination, but also an [on-time] 1800 EWR-PHL. I arrived at the gate a few minutes before boarding started for the 1800 flight, and asked if there might be space in light of my connection and the delay to the later 1829 departure. The agent said the flight was full, but that I should wait by the gate. Sure enough, there were enough no-shows that there were seats available for the stand-by passengers, including myself. I made my original connection PHL-xxx, and US avoided the need to rebook me. This did not undermine the value of a more flexible ticket; I had no expectation of (or interest in) changing my ticket, but only in arriving at my final destination with a minimum of hassle. US did not lose any revenue, as I was only given the BP for the 1800 flight moments before I boarded. It was understood that, as a standby passenger, I would only be allocated a seat once the flight was otherwise closed. I was happy with the outcome, and I would like to think that US was as well.