For what it is worth in more than 10 years military flying and 8 years civil flying I have never once flown with anyone who I had any reason to believe was under the influence of alcohol. That said, it is apparent that whether we want it or not there are new rules coming and they are a source of concern for even the most moderate of drinkers (of whom I am one).
'YouNeverStopLearning' made a very passionate statement about the disgrace of pilots flying over the limit and the necessity of seeking help for your alcohol problem. There is no doubt that if you are an alcoholic you are fundamentally unfit to be a professional pilot for as long as the condition exists, and I do not think many of my colleagues would dispute that.
With the arrival of this new legislation, the problem is now far greater than just the issue of the alcoholic - however tragic his/her circumstances may be. This new legislation will have significant lifestyle effects for anyone in flying who is not rigidly tee-total. I think I speak for many when I say that I feel very uncertain about this new legislation because I simply cannot translate this 20mg figure into anything meaningful in my own mind. Does that mean that if I have 2 glasses of wine the night before a flight (and do not infringe the 8 hour rule) that I may in fact be flying over the limit? I for one will certainly try and get hold of some device for measuring my own blood/alcohol levels (and no I am not an alcoholic).
We have to recognise that enormous new restrictions are being put on the lives of flight crew, and that to have this 20mg level in your body does not mean you are some kind of drunken yob. I want to be able to be absolutely certain in my own mind that I am not in some way endangering my future. I can foresee a scenario when a pilot will be feeling absolutely on top of things but find out via a random test that he was in fact over the limit due to a couple of glasses of wine with his wife the night before.
Our employers have a clear duty of care here. The answer has to be for company-provided facilities to test yourself prior to duty, and the option to go sick without subsequent recrimination if you find yourself over this new limit.