I had them cancel a late flight from BA to Iguaza last year. They moved me to a Midday flight that day which would have cut my time in BA, and what turned out to be the best afternoon.

To be fair I had about 5 months notice, but I had booked hotels and had change the number of days I was staying in BA and Iguazu. Luckily it wasn't one where I would have faced a penalty for changing.

As soon as the email came (yes, they did send me one) I bought a LAN flight for the next morning. As the Aerolinas ticket was a fully flexible one I left cancelling it right up to the morning of the flight. The main reason was to delay the credit going on my card so I could trigger another 2-4-1 voucher with BA (as in British Airways, not the Ciity!!), but it did feel a teeny bit good getting some sort of payback for cancelling my original booking.