In the States, DOT regulations allow for random testing amongst commercial drivers, as do many other professions that involve the welfare of the public. And rightfully so.
So why should a pilot's union proclaim they're above such testing?
I would welcome it amongst medical personnel, surgeons, maritime operators, pilots, train engineers...you get my point. It's obvious there are enough folks who can't self regulate their alcohol. The public domain shouldn't have to find out the hard way.
And if further physical examination proves another medical culprit for alcohol levels above allowable, then they're exonerated/treated accordingly. How anyone could object is beyond reasonable. It falls into the same nanny state thinking that's taking over much of the world.