The issue for me here is Cannabis testing, I'm afraid I've had to learn quite a bit about it for reasons I would not wish on anyone.
Cannabis has a "half life" in the body of Seven days, that is the amount of THC (tetrahydrocannibol) in the body is halved every seven days. Detectable amounts will remain for maybe three or four weeks.
Now I understand that the tests used for Cannabis is a "yes/no" test. So my understanding is that one bong/cone/ cigarette/hash cooky etc, could still see you accused of "drug driving" thirty days after use because there is no "Safe level" below which you would not be regarded as impaired.
So here we go again. Any detectable level of Cannabis in the system - go to jail. Any detectable alcohol in the system - go to jail.
But do you deserve it? The net effect of all this could well be pilots losing their licences,and/or their careers, or future careers for no particularly good reason.