Originally Posted by dblumenhoff

I'm curious about what this looks like on the back-end. When the delivering carrier "protects" you on an alliance carrier, what money is changing hands and how? I'm thinking of two different scenarios:
Scenario 1: Connection from airline AB to CD misconnects. CD does not have any more flights to destination today and AB places you on their own flight. Do they get to reclaim the voucher from CD? In that case isn't it really CD that is out money because they could have sold that seat (in which case, how is AB at all hurt and why wouldn't they protect you at CD's expense)?
Scenario 2: Connection from airline AB to CD misconnects. There's a later flight on CD, but obviously at today's rates it's a fortune. Is AB paying CD current market rates or do they just apply the voucher from the original flight to the new flight? If the latter, then that begs the same question as scenario 1, all of which is to say: if the delivering carrier is responsible for rebooking, why wouldn't they all widely define the situations in which they will protect you?