I definately think that dragging real junkies into school could help.
Even more so if they go in as a fully functioning normal adult like Roscco and then were locked in a room with some Heroin buried deep inside a dustbin full of dog turd and left there in full view of the kids for 2 days.
I reckon that seeing a normal person now going through shit with his bear hands to get his fix after 36 hours would have a pretty sobering effect on the kids, although Im not sure the european human rights commission would say it was fair on the addict.
Seriously though, hearing the effects first hand would definately deter *some* potential addicts im sure.