Why wouldn't a Thai recognize a Wise transfer slip? Put your name in there and send them a screenshot of the transfer and youre done. Write in Thai if it helps.
True, but for a DTV I'd seriously question anyone trying to get me to book an onward ticket. I'd try to talk my way out of it and tell the staff they're untrained and don't know what they're talking about.
I think the chances of them requesting an onward ticket on a DTV is extremely remote. The only staff who might do so, are those who automatically ask to see onward tickets for foreigners (non-Thais) flying to Thailand on any visa, because they just read the screen they see and assume all non-Thais need an onward ticket.
You can always ask for a supervisor in such cases and they'll override the decision made by the check-in agent.
Which is very, very unlikely. Untrained staff will see a 5 year visa and should in theory look even better than a 1 year extension of stay. I can't imagine anyone questioning it.
If you arrive without a visa then yes, they can ask for and demand an onward ticket.
Good question. Strictly speaking, it's a possibility. In practice, only Ranong might ask for it. I know they ask for it when arriving on a non-O multiple entry visa [at Ranong], but you can talk your way out of it (I did). All other entry points, not needed, but do yourself a favor and spend a few days outside of Thailand at least once every 180 days rather than a same day turn-around. This reduces the likelihood of being asked for 20K in cash.
Well, you might not because you could just have an onward ticket dot com booking. However, in general, you are correct and like I said, for a single entry tourist visa, you should have an onward ticket even if it doesn't get requested.