Just throwing this out there; what happens when there are two airlines involved? For example, you book DUB-LHR-SFO, but the DUB to LHR is a BA codeshare on Aer Lingus, but the flight from LHR to SFO is with Virgin?

When you return to London, and don't take the Aer Lingus flight back to Dublin, cant see Virgin kicking off about that??