@Greg **********
The crackdown was already underway since late 2024 for chronic visa runners at many borders (by land), and since 2018 ish at Bangkok and Phuket airport.
What has changed recently is for the people in the middle (so neither newcomers nor chronic visa runners), are now being denied at a much higher rate. So they have broaden who are now getting denied.
Also, getting a SETV is not gonna work if it's already clear that you are not a tourist. They will deny you entry. So can't go from visa exempt to tourist visa scheme, not gonna work.