That is "part of the result [of ____] that is definitive". Give the meaning of that some thought.
The Oneworld policy that covers baggage checking across separate tickets was part and parcel of the checking in of passengers across separate tickets. They are by design married together, as if they are separated then what's the point.
OW carrier reps -- including at LHR, MAD, JFK, MIA, DFW, ORD, LAX, NRT and SYD -- should be aware of the policy that thru-checking policies apply to the passenger and the baggage of the passenger.