Milos Zec Lufthansa from Toulouse to BKK in September 2018 DID ask. Malaysian Airlines from Dehli to BKK in October did NOT ask… Safest is to buy an onward ticket..
I did it in Jomtien/Pattaya. I needed to have at least 15 days left on my "exempt visa entry" to apply for a "90 day Non O visa". With all the requirements : 50 years, 800k on Thai Bank account for at least 2 months before application and proof of residency. In case you don't have enough days left on your "exempt visa entry", you can first make one extension of 30 days (1'900.B), giving you the time you need.
Be careful, the money must be on your Thai account (either in THB or in major foreign currencies) for 3 months prior to the "360-D-Extension" of a "Non-Immigrant-O". If you are short of time to do this, you van always extend your current "Non-O" visa for 30 days (1'900 Baths) to give you more time.
A new rule is that the 800k baths must be on you account 2 (and later 3 months when you ask of the 360-days extension) AND stay on your account for 3 months after you get your visa/extension...That means, that, actually, you need 800k PLUS your budget for the 6 months during which the 800k must stay untouched on your account. PS : instead of having the 800k in Baths, you can have the equivalent on a foreign currency account in the Thai bank, as long as it is not blocked.
