Originally Posted by
SK AAR
You may have been lucky in the past that the immigration officer (who is supposed to check that your BP is issued at BKK only) did not notice, but if you ask for a BP at the TG check-in at BKK (rather than to re-enter with a BP issued at the origin) TG will ask you to pay the supplemental airport tax.
Or they won't. Absolutes are poorly placed here as TG has been very hit and miss on this particular subject over the last few years.