This really ties back to the same thing many on these forums have said in the past. Why do we need more laws to enforce the laws already on the books?

The way this law was written anyone who is suspected of being stoned and tests positive for marijuana can be prosecuted. A person could smoke a doobie and test positive a week later. There's nothing in the law that prevents LEO's from suspecting everyone is stoned and demanding they take a drug test.

How would you feel if the state passed a law stating anyone who tests positive at anytime for gun shot residue can be charged with illegally discharging a firearm?