I guess the lesson here is if you are high and a cop pulls you over and suspects you may be high don't let them take a blood test, although I think in some states you may not have a choice. I remember reading an article where in at least one state cops carried a kit with them and could literally force you to give blood on the spot. The day I live in a society where cops can legally force a needle in me is the day I find a new place to live.