I had a flight I booked on British air at ba.com couple years ago.

CLE-ORD-LHR-CAI - all one ticket, not seperate ones.

CLE-ORD American Eagle
ORD-LHR BA
LHR-CAI BA
and return.

My CLE-ORD flight was rerouted to PITTSBURGH due to weather (january blizzards), before I boarded my first leg out of CLE, so they moved me to next days flights, no problem. Not sure why they didnt just CANCEL that flight instead of dumping everyone in PIT for the night.

More bad weather next day casued a rebooking to American Airlines plane ORD-LHR in coach, and I couldn't get a refund on fare diffrerence since I was told it was a deep business discount ticket, to say nothing of the inferior AA product vs BA. However at ORD I found BA counter and they made modifications for me in person getting me on the BA plane. The AA and BA flights leave within minutes of each other, and the BA flight had over half of its business seats unsold, just none in my "fare code" left to sell.

But I was going to miss a dinner meeting in Cairo I had planned on arriving a day ealier for, so I asked to be put on a Egypt Air flight from LHR to CAI that would have got me there like 5pm (vs. BA arrival at after midnite). They wouldn't do it. I offered to buy that ticket myself (it was only $150), they said if I didn't fly the BA flight LHR-CAI, the balance of my ticket would cancel.

After lots of arguing on the phone, they finally said "is there anything else we can do for you" I replied "yes, please find me the person in your organization with the common sense, I'll be happy to hold." They never did find anyone with any comon sense.

I missed my dinner meeting with a higly placed governmental minister. Never flew BA or AA again.