During the current crackdown on visa-exempted entry, if someone with many previous visa exemption stamps in his passport was being interrogated upon arrival at immigration (either at airport or border) attempting to enter using visa exemption again, would it help to show a valid Tabien Baan ("yellow book") that contains his name and address of residence?

I doubt it, I guess it could even open the question as to why are you living here and dont have the correct visa.

It would not help other than to prove your residence.

I doubt it, I guess it could even open the question as to why are you living here and dont have the correct visa.

What would be the "correct" visa for a person who resides with his Thai girlfriend at the address specified on the valid Tabien Baan and would qualify for the retirement visa except for the age criteria?

It's a little strange that a foreigner can reside in Thailand and hold a Tabien Baan as proof, but is not welcome to re-enter Thailand to continue to stay at that residence.

Must he marry the girlfriend in order to be welcome to continue to stay in Thailand, otherwise he is unwelcome? Would stating that he intends to marry the girlfriend help? Does this mean that there is effectively a maximum time limit set for a foreigner who does not qualify for visas other than tourist visa (or visa exemption) to decide whether to marry his Thai girlfriend, after which he is no longer welcome to physically meet with his girlfriend in Thailand, possibly resulting in a relationship break-up?

Visa exempt entry is solely for tourism purposes. Showing you reside in Thailand will just proof you are not a tourist. If you want to reside in Thailand you will have many options;

- find/create a job with workpermit

- learn Thai

- buy a Thai Elite card

- marry a Thai person

- father/mother a child who you will enrol in a school in Thailand

- invest 10 million in the country

- maybe I am forgetting some?

If you can't or won't do any of the above then it is going to be hard living in Thailand being under 50. At least for the next couple of entries you could apply for a multiple non-o visa, based on your intention to marry soon. Might work.

Just know that no visa is a permission to live in Thailand long time. Only extension of stay, residency or citizenship allow you to do that.

How did you get your Yellow Tabien Baan on visa exemption?

I was told this was impossible and I gave up trying.