As for scary court rulings, check out this one from Michigan:
In the case before the court, a driver was pulled over for erratic driving and admitted having smoked marijuana. However, a blood test did not reveal THC, the active ingredient in the drug. Rather, the test found traces of carboxy THC, a metabolite that can remain in the body for up to a month after smoking pot and is not considered evidence of impairment.Apparently, the court ruled that the carboxy THC was enough to grant a DUI. Amazing. Smoke pot, get pulled over 3 weeks later for failure to signal, and get a DUI . . . crazy.