Originally Posted by
Some person
The regulation states that you should be offered "re-routing, under comparable transport conditions, to their final destination at the earliest opportunity" so if the Sun-Air (BA) flight is "under comparable transport conditions" and earlier, then they have to rebook you on that flight. On the other hand, if the Sun-Air flight is not "under comparable transport conditions," then they are not required to rebook you. The problem is that I'm not aware of any rulings on what "comparable transport conditions" means, so it's unclear how a court would rule.
I do not see any provisions in the regulation for the air carrier to charge any money for this rebooking, so the carrier may be unable to reduce the number of points that you would get to whatever frequent flyer programme you're using.
It is a legal argument that is very unlikely to be won. People even struggled winning over Norwegian for waiting 3-4 days to get home from a long haul cancellation. Where Norwegian refused to rebook to other carriers.
Saying it is not an unreasonable request, saying there should be leeway for it, or it would be the right thing to do, might all be correct Saying they have to rebook to BA has no basis in the regulation, or the current legal interpretation of it. That of course can be challenged and changed, but that is current status.
As SK as standard SOP allows for original credit of miles when you are rerouted to a non earning airline, point loss would not be an issue