Anonymous participant I have flown them at least 7 times from Danang to BKK and never known them ask anything. As I said it will be on the instructions for the check in clerks input by the back office.
DTV_Begpacker It was another Thai feck about. At first they woukd do nothing as wanted WP as well as passport. I had a Thai with me who said that was just stupid. She went over to next tower and got copies of WP from company office. Nope, wanted the WP book. In the end I took the ATM card and withdrew every Baht and went back in the bank and gave it back. I then got on Skytrain one stop to Emporium and bought a Naim Muso2 with the rebate. Used daily :-(
After 90 consecutive days in Thailand you need to do the TM47 which is known as the 90 Day Report. You need to do this in person at an immigration office. Online is only for subsequent reports after the first if you also remained in country.
Easiest is just to get an accountant to do it for you. I seem to remebwr all I handed over was Passportand WP. As you say language issues at some and to be honest some want to avoid dealing with foreigners if not an everyday thing lol