Can you be turned away at a Thai land border due to your visa history?

@Bra****

right, my point was more that I get the impression that's largely the only limit that land borders apply. Other than that, they seem much less likely to use "discretion" to deny you than an airport, where they can decide you just look like you've been here too much. The land borders seem to just go by this 2 visa exempt per year, unlimited with visa, and at least some borders, like Nong Khai, I don't think I've ever heard of anyone being denied for any other reason, if you meet the explicit rules as written they will let you in.

Airport is theoretically unlimited on either visa or exempt, but in practice they do use their discretion if they feel you are here too much- and they can use this even if you do have a visa. Land border, less likely, and also much less problem for you if you do get denied, you just go back to your hotel and think about what you do next, rather than a immigration detention holding cell.