In Germany, at least, if you fail a breath test then the cops take you to a doctor for a blood test. (We have a friend who does this work at all sorts of odd hours; it's a nice little earner and she gets to meet lots of British soldiers.) So you are going to get nailed on the basis of a blood test in any case.
I was getting a lift in our flight surgeon's car, back to my compound in Nigeria. There was a stack of blank FAA or maybe DOT or DEA or whatever it was, drug test reporting forms there, so that I looked one over. Scary stuff! Either you fill it out, fail the test and you are toast or you refuse to sign, fail the test and you are toast... there is no clever out if you have been misbehaving. If your number comes up for that random test you had better be clean.
As noted, yes, the world has changed. 20 years ago most of us were hooting with the owls before going out to fly with the eagles. But that was then and this is now.... Either you hang up the headset and bore everyone with tales of how it was 'when I' or else you adapt to the way it is now.
There have been quite a few stories about the barman (who else, really?) blowing the whistle on his customers, come to that.
Part of the reason I used to drink is not to notice what was going on around me. That might well include some little
pr*ck deciding to get even with me by dropping a dime. Heck, some companies reward whistle-blowing!