I just dont believe there are that many pilots that go out get pissed take drugs and fly.
I agree, however with an apparent shortage of pilots it is alot easier that those least responsible individuals pass through the system or get into flying larger aircraft at a younger age when they haven't fully matured.(before all the younger guys make a fuss i'm talking about a select few). Its amazing how young kids these days actually start taking drugs and there is a reason why you pay alot more for car insurance if your under 25. Back to to thread the questionaire is a joke and CASA should focus on other issues such as fatigue otherwise they might actually have to give us drugs to stay awake on the flight deck
A possible solution: When I was doing some contract work for an oil company, the said company used to breath test us before every flight.