@NA'Ahulelua ********
obviously you don't know how the airline employee ticket work. Let me infirm you please. They're highly discounted tickets, usually employees and retirees pay a service charge if any and airport taxes. Are fully flexible, this means you can make changes with no fees or fare diferences as they're based on the fully economy or business class fare which is obviously fully flexible. You can also get a full refund on your ticket, or any unused part of your ticket. But, there is always a but these are stand by tickets. You fly onkr if there are seats available. The good thing is before we book a flight, we usually have a good knowledge of the loads of the flight as we can check then on a special website. Last August when I wanted to leave BKK, because the flights were very full I had 5 different OW tickets, one with Thai, one with EVA, KLM, Lufthansa and Finnair. Once back in London I refunded the unused ones.
I travel like this since 1998 2-3 times a year to Thailand only and of course many other places of this world, much more strict than Thailand and never had any problem. I travel with one way tickets usually I have a return ticket but not always use it. If for example I gave a round trip ticket with Thai and at the airport the check in desk advise me that the flight is very full I can quickly issue a OW ticket with EVA which departs 5 minutes earlier from London. The immigration never asked me to show a return ticket in all these 25.5 years, maybe because I never created any problem and always left within the 30 days. Only one time last November when I was flying from Da Nang to London via BKK an immigratoon officer asked me how long I was planning to stay stay in Thailand . When I answered only 5 hours as I had a flight to London, she stamped my passport giving me the usual 30 days, without asking to see my ticket to London.
They ask me more questions when I fly to the US and I used to travel at least 5 times a year as I was working for an American company and I have a visa.