I have not ever said I'm against testing although I have said I think it an binadequate and misleading tool. But it should apply to all who have serious responsibility. Not that you've evver been interested in what I think; you've always been far more interested in telling me. You're being repetitive and tiresome, so let me just apply your sort of reasoning to the issue and I'll leave you to fulminate unbothered.
By the John LaRue Principle only those with potential to cause bodily harm need be tested. Therefore user-focussed drug-law enforcement is an entire waste of justice sytem resoiurces, and it matters not that mechanics, mechanics' supervisors, the folks who determine how often vehicles should be maintained, or the standards their drivers or maintainence workers should meet might be passed out on the floor pissed as newts. In fact it doesn't matter how drugged anyone is as long as they aren't operating vehicles—or other such devices one infers—with potential to inflict bodily harm. What that means is 'direct' bodily harm, this excluding boozing supervisors who direct workers to exceed the speed limit as one specific example cited. Thus the class of 'LaRue acceptable' drunkards, junkies, hopheads and cokefiends would include those who certify scaffolds and safety equipment, food service and sanitation inspection and possibly even medical personnel not doing actual hands-on clinical work.
What is peculiar in this, is that LaRue uses this Principle to align himself with a union, to limit testing. Shows how open-minded the Principle is.
There, wasn't that fun!!
PS: Rude of me to ignore your direct question, sorry:It would identify drug-using managers cheating the employer out of the sober expertice they're being paid for. Once identified it might actually be possible to remove them or correct their behaviour and performance. Just like the drivers. Duh!