I just found out that the CX flights HKG-HAN (no codeshare, CX metal and flight number) are not permitted as part of a oneworld Explorer RTW ticket. Just out of curiosity, can somebody shed some light on the rationale behind this? CX will gladly fly me from HKG to India and back on a OWE but they won't let me on the 1+ hour flight to Hanoi? Makes any sense?