Originally Posted by
HarryKUK
If you are involuntarily downgraded (whether 2-4-1 or not) and you refuse to accept what's the worst that can happen?
Ultimately I would see this a breach of contract, so it would be down to you and BA to come up with a reasonable outcome and if not you're off to a judge or mediator. BA do have quite broad powers to deny boarding, so I don't think you can insist on being carried, but clearly if BA don't come up with alternative suggestions, and a judge deems it to be "involuntary denied boarding" then BA are on the hook for both a refund and up to 600€ compensation and/or any replacement costs on alternative carriers.
Generally it doesn't come to that, the only real sticky ones are the once a day flights to and from LGW, where there frankly isn't usually a sensible alternative - future flights are also fully booked and alternative routes are unattractive to all concerned. For LHR a combination re-routing options and the ATM card tends to prevent too much pain.
I would guess the main casualties in this area, incidentally, are WT passengers at LGW going to TPA and MCO, I often see them being rebooked out of LHR to MIA. These tend to be infrequent flyers and while most of us would perhaps regard a LHR-MIA routing as not a bad outcome, it probably doesn't feel like that to the people concerned.