I was asked at DMK in 2019 as I was returning from a visa run from Malaysia by air after doing tourist visa runs for 1.5 years. The officer apparently marked me on my last visa run, but didn't mention it to me then, although I remember him asking me what I was doing here. I just answered whatever, and he shrugged and gave me the entry stamp. This time however he asked me aside and asked me what I was doing here for 1.5 years, had all my visits printed out in front of him. I just answered I stay here with my girlfriend and live in my condo. He then asked me to show him my cash. I just had 7-8k baht with me as I wasn't aware of the 20k rule then. Earned myself being blacklisted, but when I entered the country again with a new passport on landborder from Cambodia 5 months later, I was asked aside and had to sit there for a while until the friendly police officer sorted me out. He asked me what the reason for the blacklist was and I just said "no cash money", he smiled and nodded and that was that. I did have to fill out a form though which asked me how much money I had on me, which you can be sure this time I had enough. Wish I was active in online groups and forums back then, well, lesson learned.