@Gur ************

It means you have to get a tax # and pay tax on income brought in to the country. Your assumption on double taxation hinges on whether a double taxation treaty exists between Thailand and the other jurisdiction in which you are paying tax.

@Mark ************************

Hi. Just for clarification, are you saying your one friend had already done two land crossings this year and was allowed a third land border crossing?

Did you originally enter on a Tourist Visa or did you enter Visa Free? If it was the latter it definitely wouldn't be totally unheard of as that would be 4th visa free entry and you would have been looking at near 8 months of continuous living on visa free entry and extensions. And you didn't really say what was going on last year so if you were in Thailand end of last year that looks even worse.