Today, I visited immigration at Lak Si Square to extend my 30-day visa exemption obtained via a land border. Despite forgetting my TM.6, I thought I would try my luck, and I managed to secure the extension without it. I went on Google Images to see what a TM.6 looked like and used the code from that to fill in the form. Nobody asked to see it or for it to be scanned on paper. If you’re in this situation, it’s always worth a try.
TLDR : Answer Summary
A user successfully extended their 30-day visa exemption at Lak Si Square immigration without a TM.6, indicating that sometimes exceptions can be made. Other commenters noted that the TM.6 card has been suspended for air entry since COVID, suggesting that the need for it has diminished.