Yesterday evening, AC864 to LHR was delayed by 4 hours due to a mechanical failure. I had a connecting flight on BA booked on a different ticket, so no chance AC would protect me. This second flight was also very restricted so I was quite worried I would lose it and get stuck in LHR on a pre-Christmas weekend if I did not show up on time. Therefore I was considering canceling my trip and losing my BA ticket as it looked as the best solution in the situation. Still, I went to the lounge and talked to the concierge about my situation. She said "let me see what I can do", called BA, negociated with them, as they were first saying they could not do anything, convinced them that it was really not my fault and was finally able to reschedule me on a later flight for 60$. As a matter of fact, I am currently in the BA lounge in LHR T1 (quite nice actually), awaiting my connecting flight. No need to say I was very impressed with her dedication and the help I received. So everything is not rotten in the state of AC...