Correct. I was speaking generally. Every individual situation is different. A person who retains tax residency in their home country and has a permanent home there, will not be required to pay tax in Thailand, irrespective of how many days they are in Thailand
I'm only stating the law, not what will actually happen. With advanced technology it would be possible to trace ATM withdrawals made by foreigners, the same as foreign cash exchanges, but I agree the cost involved versus the amount of tax which could be recovered would make the exercise uneconomical.