People have crossed land borders for as long as it has taken them to be processed out of Thailand. In and out of the neighbouring countries and back into Thailand.
I do think the MFA should be responsible for telling people their responsibilities when they issue the visa. Immigration do when obtaining a visa at the office. You actually sign off to acknowledge things and that you understand penalties for overstay etc. In the case of DTV I think the MFA are remiss here. When could or should Immigration tell DTV holders?
People have written to themselves as employees from themselves as Directors of the company authorising remote work from Thailand. The company stamp, seal or "Chop" is pretty much an Asian thing these days.