There are no longer any Tax ticket booths. All taxes are collected by airlines now.

I arrived on TG last weekend, Saturday at 534am. I had a 9 hour layover and went into town. If you already have a BP, then it should be ok. But I didn't as TG couldn't issue ongoing BPs with SQ, and SQ wouldn't issue any BPs unless 2 hours prior departure. So I had to get one from SQ after my day jaunt, and SQ agent refused to hand over BP until I paid my tax.

They said that if I stayed inside the restricted area and notpass through immigration, I would be exempt from the tax. So I had to cough out the 700 Baht before they would hand me the boarding pass. No amount of arguing helped.

The old system worked when one had to buy the tax coupons.