I have a hard time thinking there's a problem here. I mean, if three beers a night will kill a person in the long run then the authorities need to be clear about that. It seems like that guideline is more due to the fact that alcohol is dangerous in excess -- excess meaning drunk -- and also addictive, which feeds into the danger, in excess.

I go months at a time without drinking, and generally stay between 2-4 drinks when I do, but as soon as I hit that 4th I want to keep going and have a hard time stopping. If I were to follow your program of 20 units per week it wouldn't be long before there would be trouble. That's problematic, IMO.

18 years without being drunk? You've got the best of both worlds.