Anonymous participant 146 John Stanners is mostly correct, however a non-resident as determined by the DTA is not required to file a tax return. And as Tod has said, there's not one person going to jail! That's a ROFL comment. Next you'll be saying they'll have their visas cancelled!
The DTA can determine tax residency. If the DTA determines a person is NOT a Thai Tax Resident, there is no requirement for that person to file a tax return in Thailand unless they are generating income inside Thailand
The DTA also allows for an habitual abode in two countries. You need to read Article 4. "Up to" is not a defined amount. It takes only 180 days per calendar year to be deemed a Thai Tax Resident, but retaining tax residency in another country brings the DTA tie-break into the equation. Every situation is different. The tie-break can go down to actual citizenship
Anonymous participant 146 Totally wrong. I'm referring to Article 4 which determines tax residency. If a person has dual tax residency the DTA determines which taxing authority has sole taxation rights. You need to read it.
It's totally legal. Article 4 of the relevant DTA covers it. There's a tie break formula to determine sole taxation rights. The DTA is covered under the Tax Code