But the problem with all these tests is none of them are ever perfect. If you use a mouthwash, you'll come up with a BAC. You eat iirc three cherry ripes (some people do) you'll come up with a BAC. Sounds way too much like Big Brother for me...
A few years ago before I was a pilot, I applied for a job in the forestry industry (a well paid job that I really wanted), and I had to have a pre-employment drug test, to my amazement I tested positive for opiates. I was literally shown the door and someone else got the job.
I have never touched opiates in my life (even codeine), after talking to a few people and thinking about things I came to the conclusion that a poppy seed covered filled roll I had for lunch caused the positive reading....