I asked a contact who works in the airline industry in Thailand for his take on our discussion about Proof of Onward Travel (let's call it POOT ). Here's what he wrote to me:
"If you take a read on the Ministerial Notice, which is the formal and final "word" on the matter, it does say onward ticket.. specifically it says confirmed "onward conveyance". The part that's hard here is that ALL Thai notices, laws and such are ONLY written in Thai.. and only those that appear in the Royal Gazette are formally accepted as "law" Any English translation is just an approximation and not valid for determination. And thru this translation 'air' is added as the translation leads to this.
"The agent you are talking to in LP is most likely using the high level overview. Each airline sets their own risk level as to how close or not do they wish to go in interpreting the rules. In the end, the Immigration Department will make the final call as to admissibility or not. Some airlines based in part on their past experience are more willing to "take a chance" that these minor -- but still technically required -- elements of entry won't be asked or enforced, thus a lower chance of encountering an "inadmissible" and thus a carrier fine for transporting him/her. So, some airlines might take a less-than technical interpretation of the ruling -- as what is in TIMATIC (the IATA database containing cross border passenger documentation requirements - my note) -- others might take a more strict interpretation. I think this is why Checkingirl says she only looks for 6 months (which is the norm for almost all countries) and not the POOT specifically.
"If you look in TIMATIC, which is what most but not all, airlines use to determine documentation requirements, it does state that POOT needs to be there and the form as well. Again, TIMATIC is using the English translation of what is known from the Ministerial Reg."