sambb. we were in business class on AA 2 weeks ago, connecting to BA in LHR with 3 hr layover. None of our three checked bags made the connecting flight. Normally we don't check bags, but we were on a 2 week cruise and just had too much stuff, plus my rollaboard that I carry on on AA is too big for BA's rules.
We did get the luggage the next morning, but it made the start of the trip stressful.