I'm not sure if it's regularly checked, but I wrote a recent post and suggestion about this in the "questions for the CX faq". Specifically, many fliers are

a.) Not aware to even go to the CX forum for information on Dragonair
b.) Once they get here, not aware Dragonair is a fully-owned affiliate of CX, and basically all rights entitled to OW and CX status pax are given to them when flying on KA metal, just as with CX.

Yes yes, if people go to websites and such and such they can figure it out, but if the problem is routine (as it seems to be, just talking informally with US/Europeans travelling through Asia many seem to have no idea about the connection and ask similar questions as the OP) then I think we might be able to engineer this in a more user-friendly way. Dummy-proofing, so to speak.