I'm not sure i would get terribly excited about this, it's the same question they asked when the landing card was issued many years ago. I know when I fly out of Manchester I will use UK as my departure country even though I pass through Doha on my way to Bangkok. If you look at the TDAC for UK people there is also a separate Scotland option!!! So you can choose!!! Also they have choice of cities where you live back in the UK, the options here are all mixed up!! You have a choice of cities and counties!!! So the system isn't perfect so make a choice and enjoy thailand
You can only apply for a non O-A outside golf thailand, so you can apply while you are in Belgium. An O-A visa typically requires health insurance from an approved insurance company ( these are named on the e visa system ) like axa for example, you also need a police or criminal check and a health certificate. You will need the equivalent of 800k baht or 65kbaht monthly in a bank account but this can be your Belgium account does not need to be thai. Yes you can open account in thailand with a long term O-A visa. The first year of the O-A is multi entry with the option to get 2 years if you time your last entry. You don't need to inform anyone if you leave after 5 months or any other time
Just something to think about a thai bank will.only guarantee 1 million baht if the bank is in trouble so if you plan on having more than that in your account I would have 2 different accounts at 2 different banks
it depends if you are on a retirement O visa or other long term visa then you do not need any onward travel or departure details the airline will just ask to see your visa. If you are traveling on a visitor visa or visa exempt then you airline may ask for onward travel details but you would need to check with the airline
the question was about filling out the new TDAC on arrival in thailand and whether you have to have a departure date to complete it. A departure date in not mandatory when filling out a TDAC.