Any money that you BRING to Thailand (i.e. ATM withdrawals, paying rent, paying restaurants, hotels, shopping with your credit card) is considered 'Thailand Remittance Expense' and is taxed if you are tax resident in Thailand. Anyway, I am not a tax advisor so they can tell you more reliably.
Yep. I did it. I am from Spain so I wanted to save myself the hassle. I went to a tax advisor and now a tax resident of Thailand (acknowledged by the embassy of Spain as well).