Flying Lawyer
I always read your posts with great interest, and learn a lot from them. Thank you.
As far as the 20 mg limit is concerned, I believe you are correct in as much as, it was a policy decision based not on ANY scientific research, regarding human performance (I believe alcohol is still a banned substance under the terms of the International Olympic Committee, since in some situations, and in small quantities, it can serve to OPTIMISE fine motor skills, such as those demonstrated in shooting!)
As I understand it, 20 mg was a compromise between the 'machismo' of politicians, who would have been perfectly happy to mandate, a zero rating (whilst pickling themselves in the commons bar!)
And the fact that current technology, will only accurately measure blood alcohol levels down to 20 mg.
As a 'sobering' (excuse the pun!) thought, I have heard rumours of teetotallers, who produce background alcohol levels above 20 mg!
Finally, if such a limit cannot be justified on the basis of degrading my performance, is it an infringement of my human rights?