All the time.
Every time a friend gets an international category, I give them the 'dad chat' about randoms and 0.02 from the FAA and 8 hours bottle to throttle don't mean jack outside the US. They randomly test, OFTEN, the metric system can detect the presence of alcohol on a much more accurate level where the US calls it 'undetectable' and "8 hours bottle to throttle' is about the dumbest rhyme ever and means nothing.
You can satisfy the rhyme, but still be absolutely in violation of having a traceable amount of alcohol in your system. Hell, I use 14 hours absolute minimum between finishing drink and my wake-up time.
Some airports even make it a sport. I was speaking with a gate agent at a major European airport a couple weeks ago and they get 600 Euros per 'bust'. So if anyone you have contact with has a hint that you're impaired, you get called for a 'random', and you test positive, BOOM, cash money and they catch people all the time.
Same airport notorious for stepping off the bus, walk into operations and there is often a line of people to take a breathalyzer test before entering.
It's not a 'witch hunt' if they keep finding witches.