I think it really depends upon location. I've never bought in HK, so have no idea. I do know that you'd have to be insane to buy online from Vancouver or Bangkok. Even IF you had to get a seat, you could (if in MPC) buy a cheap ticket, then call CX and change dates (getting either priority waitlist or guaranteed seat, depending on your level). Can't see a reason to buy online, unless it's for business and cost is no object....

On the other hand, from a place like Hanoi, there are no consolidators, and the CX price online is about as good as you'll get...The differences make me laugh. For example (this is coach): a ticket Hanoi-Tokyo is $1,000, while a ticket purchased in BKK (BKK-YVR) is $600!?? Sometimes I have trouble making sense of the air travel business....