YouTube - bangkok ladyboy
Well, it's not our fault many Asian guys are not masculine enough so they get away with such things. This one above I found on YT would fool some, too.
I'd make sure I'd check out pictures and videos of ladyboys so as to be able to spot them (and avoid, naturally). Or take a quick 'feel' to confirm gender if on a carnal hols.
I've been watching some vids and, hell, I'd have no clue sometimes.
Then, when you see one like this, I'm sure being drunk you wouldn't mind post-op one looking like this one (if you ever got to know).
YouTube - nong ploy thailand ladyboy