I have openly without issue. Notice more and more people here doing it too . Brought 2 months stock of my vape stuff for recent visit. Extended a month and bought extra sock online delivered to hotel.
I started coming 3 or4 times a year and after a few years with loads of stamps I got taken to separate desk for 5 mins and questioned. When I pushed back asking what the issue was it seemed they thought I was taking the piss getting free exemption and not getting a tourist visa. I started getting a visa once a year and all stopped. Arrived Sunday on exempted in Phuket. Was asked why no visa- I said because I only stay for 28 days- all fine. Had return tickets but not requested