As SLF, I think there's another wider factor...
...to be considered. The current puritanical attitude to alcohol, any alchohol, as the root of all ills and risk in society notwithstanding, surely there has to be a sober (geddit?) cost-benefit analysis of this kind of testing and enforcement regime at these vanishingly low limits? Clearly I wouldn't want to fly to Ibiza with a pilot up front who was impaired by alcohol, but we also know that modest (note modest) alcohol intake is actually demonstrably good for people. Good for their physical health and their psychological health. Witch hunts and artificially imposed stress are equally demonstrably bad for people. If there was a real problem with pilots flying ratted, and safety being compromised, then draconian and thus demonstrably damaging attempts to address it would be more than justified by the nett benefit. Ditto if the only reason the sky isn't full of drunken pilots weaving around the airways is that such a draconian regime is in place. But given that it appears that there isn't a problem (by which I mean statistically significant numbers of broken aeroplanes and dead/injured people associated with crew alcohol misuse), has anybody considered whether the number of deaths and serious injuries that might result from the impact on crew health and well-being of attempting to effectively force all aircrew to become tee-total or of the additional stress on aircrew of the aformentioned enforcement regime?
Come to that, what about even just the cost (headline and consequential) of the enforcement regime itself?
In an ideal world, nobody would ever fly a plane with any measurable alcohol in their systems at all, but all would also be relaxed, in perfect psychological health, free of any artificially induced stress and as fit as they could possibly be in every respect. This not being an ideal world, and those two conflicting requirements being somewhat mutually exclusive to an extent, where do I as a passenger want the line to be drawn?
My answer is that if a witch hunt culture on enforcing very very low alcohol limits actually makes me less safe overall, and costs me a fortune in the process, I don't want it, any more than I would want to be flown by a pisshead.
Pick the bones out of that if you like.