Would you agree to work place drug testing if weed was legalized?

That's very interesting. I'd never heard of this type of test before, only the more common blood metabolite test. It seems from a quick search that THC levels in the blood are very high immediately following ingestion and then taper off very quickly to almost nothing, even before the high has run its full course. The results still seem mostly inconclusive, but this type of test could be much more helpful in determining if a person had smoked marijuana within one or two hours of the test. After that window of time however this test would show almost nothing and at that point the individual, depending on tolerance and such, could actually still be high. It's kind of the opposite end of the spectrum of reliability.