Not so many years ago, a largish Middle Eastern airline stumbled upon the fact (in farcical circumstances) that one Korean flight attendant was doing all the emergency procedures renewal exams for many if not most of the Korean flight attendants in the company.
The Korean FAs would simply swap IDs and the girl supposedly doing her SEPs would do the flight for the one girl who knew all the answers, and so it went on, day after day for quite a while until one day one of the girls operating a flight with the exam girl's ID blithely announced at the crew briefing that although her name on the GD was XXX, it was actually YYY, so please call me YYY. Only then did someone note that the face on the ID wasn't the face in the briefing room.
Having said that, I found most of the Korean girls in that same largish ME airline quite pleasant to fly with (willing to travel, a different demographic/personality profile than the ones who work at Korean perhaps?) and almost without exception, NOT someone to try to outdrink at the bar. Those ladies could handle their grog like a wharfie.