[Two4]

While your comment addresses the most common factors contributing to addiction, it doesn't really answer the question of how to let children experience the consequences of addiction in a way that's low stakes and not irreversible.

[whythre]

I am not sure it’s possible. Part of what defines addiction is that overpowers the will, which isn’t safe. It also is typically a long term decent, a series of poor decisions in the grip of a disease. Not easy to model.