When you checkin and give them your passport, they will check to see if you have a return ticket in your reservation. At that time they will ask you for whatever documentation you have to allow you to stay in Thailand if you don’t have a return ticket.
Tom Edwards why would I be? I follow the rules and respect the countries law when I travel . I’m not disrespectful and arrogant……for those of you who don’t follow the rules consider yourself lucky…