I have been nonreving to Thailand and HongKong lately.
Be prepared with a lot of ZED tickets, as it is not very common to exchange ZED tickets with different destinations and city pairs, even if it is exactly the same fare and taxes. Asian agents are not usually familiar with these procedures, some of them know the rules, but everything can happen.

Employees there are very very focused on revenue passengers, and not really prepared to list, check-in, accept, and change flights at any moment and any counter. Mainly they will have special desks which such STAFF CHECK-In counters, that will put you on the standby list, and will make you to come back aproximately at the time of the flight initial close out. At that moment they will tell you if you have been accepted, and will print you out a boarding pass. Then you will have to get into the terminal, security, customs, and then your flight.

I have always thought that it is impossible to know if any revenue pasenger is missconnected or lost at that stage, so issuing standby boarding passes to be able to accept someone at the gate is the best. But they do not want anyone to disturb asking for a seat at the boarding time. I am absolutely sure they leave the gate with open seats all the time.

How can they know if someone who did online check-in is at the airport 50 minutes before a flight?

It happened to me both times that when they put me on the standby list and make me to come back to know if I have been accepted, they retain the ZED coupon, so if you want to try to standby at any other counter of airline with the same coupon, you just simply can not. Once I asked for the ticket, and they told be that I had to be taken out of the standby list if I retained the coupon with me.

Does anybody have a clue about why do they do that? It has never happened to be in Europe or USA.

I just simply finish with the problem issuing as much tickets as companies flies somewhere, even if it is the exact same ticket, because Asian airlines do that all the time!

So I would be prepared with a lot of different tickets to be able to deal with all of them.

The nice face of the deal is that they are so kind and good onboard, that they worth a try.