Guess it also depends on what mood they were in.

I flew DBV to LGW and as the flight was too late an arrival to get on the last EDI flight I was going to stay with a friend in west London and get the morning T5 flight to EDI.

My DBV flight was in 20 mins early so I dashed to the ticket desk and asked nicely if I could jump on the last EDI flight. The lady was great and mentioned how the ticket didn't permit it but let me make a call. She managed to get me moved and I ran to the gate and made the flight.

Being hand luggage only and flashing the Gold car probably helped too.

So never expect it and if they do move you look on it as a little bonus.