How can we make our children more aware of how dangerous it is to become involved in the occult?

Several children in my local middle school were found playing with ouiji boards during their lunch period, and some of the girls have been carrying around books about how to do love spells so that they can get boyfriends before the upcoming dance. Most of the kids thought it was "no big deal". How can we teach our children the difference between what is harmless fun and what is dabbling in the tools of the devil, especially when society makes the two so ambiguous?