Wow.. this is very good info. I know I have been asking this same exact question for months on other OP sites with no responces so far.

Where I live it's just crazy. I know of a guy that took his pre-employment drug test while he was stoned out of his mind, and had taken many other narcotics the previous week. They did one of the cheapo instant strip tests... He went to work the very next day! (PASSED!) On the other hand, we have places that do random hair testing.... while some others search everyone for fake urine before tests. It really does vary from being extremely strict to being "looking the other way as the water is runing" (some just want the tax break it seems)

But, I have yet to hear of a single case where a person showed their OP scipt for a positive test result. I would be most interested in the legal outcome.