FYI!!
Please make sure to fill out the TDAC form before entering Thailand.
Today (May 2) at Suvarnabhumi, they only asked me to show the passport and TDAC—nothing else was questioned. All they said was "Oh you hold DTV. Enjoy and don't forget to fill TDAC next time too."
If you haven’t filled it out online before reaching immigration, they’ll ask you to do it first. Quite a lot of people hadn’t completed the TDAC form. It seems like the line at the TDAC filling area is even longer than at immigration.