Hi, I actually did asked the Customer Service by phone and also email and they said Korean Air does not approved the C.A.R.E.S. However a friend of mine just recently fly using Korean Air though she was not pleased with their service, she was able to use C.A.R.E.S. with no problem.

It seems like it depends on the Flight Attendant...though it would be really nice if Korean Air can put their act together and set a standard rule so we as passenger won't be in the dazed and confused stage.