Unlikely they'd need that. There's actually no 90-day law in Thailand for IDP. But if they did want that, then yes they could do one 90-day report, and then forget about the rest for the next five years! 😆
Correct. When I was on OA visa with second "free" year, I went almost four years without filing a single TM30 or 90-day report. Yep, I was "illegal" but realistically no-one gives a hoot! And worse case scenario - 2000 baht fine. Compare that to the money and time I saved not traipsing to an immigration office? ✅
A DTV holder who bounces within 180 days also doesn't need to do a 90-day report. Immigration at airports and land borders have zero interest in 90-dayers!
You cannot live in Thailand on tourist entry stamps. Immigration officers are not stupid. They see a pattern in your behaviour, you will be denied entry and a possible black mark on your immigration record
I think by EXIT stamp you mean RE-ENTRY PERMIT, which is something totally different. You can get these either at an immigration office or at the airport. 1000 Baht for single, 3800 Baht for multi.