Black Knat
As a frequent traveller, I have been following this thread with interest, as my life is literally in the hands of professional pilots times several times each month and I have great respect for the skills, knowledge and attitudes of commercial pilots.
However, your questions trouble me.
There are legal limits for BAC when performing an aviation related duty.
In my day job I have to comply with some regulation which strikes me as being overbearing, but as a professional I comply.
Maybe I am reading an implication into your questions that you did not intend, in which case I would ask you to forgive me, but it reads as if you are making an argument that the laws are unjustified.
It only takes a further leap of logic to infer that unjustified laws can be paid lip service.
I hope I am wrong in my analysis, since my cut on professional pilots is that they are just that and that they would comply with regulations as a matter of course.
I would also like to express my support for the professional pilot community, who have flown me safely going on for a thousand times in the past 20 years and who seem to be the centre of a media frenzy at every opportunity these days.