Originally Posted by
angatol
Even on one ticket I've had problems getting one airline to issue BPs for another. If they don't have any real incentive and can just tell you that you have to do it at the connecting airport, you don't really have much come back. However, if you have a "bag", they at least have a motivation to tag the bag to the ultimate destination resulting in a connected itinerary.
The last few times I've deal with cross ticket connections in Spain with IB (IB-IB and IB-BA), they haven't checked bags through and I had to recheck at MAD. The time they did, they used a manual baggage check and the bag got misplaced at LHR.