just few days ago i had KEF-HEL-SIN on AY and SIN-HKG-TPE on CX.
at KEF ground agent helped me short-check to HEL only, so i could try my luck at HEL. (i didnt expect third party ground agent in Iceland to be able to thru check to CX so i didnt bother)... so picked up my bag, went to Platinum checkin (i was flying J on both AY ane CX and OWE) and asked if they can tag to HK. they simply asked if this is same ticket, i said No, so they refused.. i ended up clearing immigration at Sing and recheck (i knew it was coming) so instead of a 90min connection if the bags were checked thru it became a 4hr run..
i guess there is cost AY pays ground agent to load bags to another airline. hey here is suggestion AY: why dont you offer interline bags at additional cost say 25eur? i would have happily paid that.... i think actual cost of loading bags is about few eur each ground agent charge (a recently debated carosel fee at HKIA is about 20eur cent for one bag loaded to carosel) so heck i am happy to pay it
i guess this rule is to protect their high yielding routes and direct business to a codeshare journey at inflated prx. but AY business model is hub*spark from asia centers via Hel and there isnt codeshare on all routes.. somehow such user pay scheme might be another successful addon fee if they wish to penetrate deeper to peripheral Asian destinations, as current setup is prohibitive for customers not based out of AY outports