I did lead with "I am probably fooling myself...", Unwell Raptor. I just cannot help but think that anonymously, and possibly maliciously, reporting aircrew as being drunk has hugely expensive implications, both for the airlines in delayed and cancelled flights, and for the aircrew involved in career threatening legal action.
I cannot help but think the airlines will eventually demand something like what I suggested above if such reports become frequent enough to affect the bottom line more than they are willing to bear. Sadly, I suspect that they will come up with some system in the meantime that will be even more intrusive into our already overregulated lives.