https://aseannow.com/topic/989464-denied-entry-at-suvarnabhumi/
Start with this thread way back in 2017.
Can post many others but it's boring.
Seemed to reach a peak in 2018, 2019 when it was common.
Folk refused entry using too many repeat entries via air.
Sometimes only spending couple of days out of Thailand.
This was most common at Bangkok airports.
Some folk were even selecting CNX as a safer entry point.
Since covid things have had a reset due to the amnesty and covid extensions for couple of years.
Rest assured overdoing visa exempt entries and resulting in refused entry will start to pop up in the future.