Not that I understand how these breathalizers work, but I understand that false positives can occur if you have a lot of keytones on your breath from a low carbohydrate diet etc.
Also as a proffessional one's reputation is at stake. So if a disgruntled person decides to "get their own back" and report you for smelling of alchol, which proves by blood test to be untrue surely you will have legal grounds to sue for deformation of character libel etc., along with your company who no doubt had to replace you at the time at great expense.
There has to be some sort of come back for an inocent individual.
