Originally Posted by
kittiyut
Yep, you'll get a sticker (that easily falls off) to put on your shirt to identify yourself upon arriving at BKK. You won't have to go through immigration again, not even carry-on baggage screening! I guess someone else will have to answer you about the buggy service, don't have that experience of domestic C/F -> Intl F.
That is not correct.
Immigration is indeed taken care of HKT, but to gain access to the international departure level all pax must pass through transfer security at either the D/E/F/G confluence or the D/A/B/C confluence.
[bolding mine]