Alf TG
Ref post #8.
The Astute shooting of the WEO took place because the culprit was a nutter - being over or close to the alcohol limit probably influenced his behaviour, at the time.
The trouble is that being pixxed doesn't mean you're a murderer. Breath/blood testing will uncover individuals who are over the limit whilst on duty. Well and good; they shouldn't be allowed to operate/handle potentially dangerous kit or be in a position to cause harm. But don't imagine that it is a defence against nutters.
It's just the relatively easy knee jerk reaction to an extraordinarily complex problem. It's far more difficult to understand and guard against nutters.
Rgds SOS