I believe you would need the supporting documents of an already formed company or the supporting documents of a company job offer before you could get any B visa.
Chaing Mai was the first immigration office to resurrect the TM30 rule. The latest I'm reading is they have relented on requiring a TM30 for those extending a 30 day visa exempt entry but are strict on the rules for those people extending actual visas and require the TM30
Yes they do BUT if they don't, YOU get fined and refused the TM30. The onus is on both of you to report and be reported. I'm simply trying to help you be prepared. I.know exactly how this works. I'm not here to argue who is responsible. It makes no difference to me if people spend 2 days of there time doing this or not BUT if your paperwork isn't correct, you will be backwards and forwards until it is. You simply won't get an extension until it is.
As I've said, the image I posted is what immigration have been handing out to people.