You could be right, tacticalogic. But I've know a lot of kids on drugs who begin to despair that they can really break the addiction. This would help them do so. Though many would go back to drugs, all would know that they could give them up if they had to. That's a really valuable lesson for an addicted teen.
Maybe, but realistically, you're talking about kids who are truly addicted. From what I know about the psychology of addiction, there is nothing you can offer an addict as an incentive to quit until he's ready to quit. What evidence do you have that this would help them break their addiction?