Btw, I don't think that running workshops/seminars is actually "working", despite what some clueless people say. It's more like a hobby or meetings of like-minded people. Do you need a work permit to do a hobby?
Only in someone's schizophrenic mind. Look at all those answers in this thread. People are completely detached from reality and live in their own imaginary world - the definition of schizophrenia.
It's the matter of interpretation what "working" means. And what is actually considered "working" by the authorities. Somehow I doubt that anyone running seminars in Phangan has a work permit.