@Luit ****************
there's also nothing in Thai law about limiting tourist entries either, but they do it. In Thai law you could visa run on visa exempt entries back to back for a decade, there is nothing *in the law* that says you can't do that.
It's why they come up with another excuse, if you actually look at the technical reason for denial for any of these visa runners it's never "in Thailand too much" or "over 2 visa exempts this year" because they are not one of the legal reasons to deny entry. They usually use "(2) Having no appropriate means of living on entering the Kingdom" or "(3) Entering the Kingdom to earn livelihood as a labourer or to be hired to do physical work and not skilled, or technical work, or to do other works in violation of alien working laws", there are 12 legal reasons for denial in Section 12 of the Immigration Act and they need to pick one and put the number in the official denial. And they do this, but it is never "visa run" or "too many entries" because that is not an enumerated legal reason to deny entry.
It's policy, and they have a lot of freedom in setting policy as they like. They don't actually push a law through parliament when they have these periodic crackdowns either, they just change the policy.
Laos also has a no same day return policy for visa exempt now, but doesn't apply to visas. It used be particular to Malaysia, and then Cambodia, but it has spread. And that policy does seem to be coming down from high, to crack down on "visa runners".