Participante anónimo each country has weak visas and strong visas. Although I'm a DTVer myself (remote work, tho) I know this visa isn't strong compared to others. So the advice is, don't plan to make a life in another country while on a temporary visa (yes 5 years is still temporary compared to permanent visas).
Participante anónimo As I said, let the IO decide. If it's not a rule or requirement, the IO would tell you're welcome to enter again, otherwise, the IO would tell you that you can't enter because your course already finished long ago.
of course I don't believe that specific troll post. But what I say is that it's not out of place for an IO to check you still fulfill the requirements of the visa you have. I mean, they've done it all the time with other types of visas too.
Participante anónimo then one can tell to the officer: "I did my muay thai course already, and finished it. Now I'm just a tourist (on the DTV) for the remaining 4 years, any problem with that?"