In fairness, I should point out that AA LHR staff have been exceptionally friendly and helpful to me on several occasions. In particular, last summer when a BA mechanical in BCN caused me to miss my AA connection at LHR, the BA staff couldn't be bothered by it. We were flying on Biz award tix and AA had no seats to the east coast for a day and a half due to something major going on in London, though I can't seem to recall the event. Anyway, BA actually expected us to wait for the next available AA seats and at first wouldn't even offer overnight accomodations. No matter what I said, their only response was that we were on award tickets and they weren't going to re-route or re-book us, period.
The AA folks, though, did their best to resolve the situation - both by pulling out all the stops to get us on an AA flight that day (which didn't work out, everything was overbooked by like 75 people), and by calling a BA duty manager on our behalf to insist that BA give us their only avaiable seats that evening (in F!). In the end, BA caved and gave us seats (in J; I suppose they gave cabin rolls to some more deserving BA elite!), but I don't think it would have happened without the pressure from the AA staff. Even though AA hadn't caused the problem (and the EXP desk in the US couldn't help us out), the LHR staff were not only sympathetic but also extremely helpful. So I guess there a few folks there that earn their salaries and a bit more... ;-)