I've had success everywhere (including HKG, PVG, MNL, SIN, DPS, etc.) except DMK. In fact, of the past 4 times I went to DMK I was denied 3 times where the agent told me you need a stamp on back and to get in the other line (which was at LEAST 2 hours long at that point). I haven't had any issues at BKK but the last time I went the agent did look at the back but didn't say anything. Kinda makes me want to avoid DMK if I can fly to BKK instead going forward. I told them that no stamp on the back meant I could go anywhere but she was hell bent on sending me to the end of the longest line.