I say use at your own risk because nobody entirely knows how ouija boards work. I have a theory that these tpes of spirit communication devices open up a person's coporeal "firewall", allowing spirits to possibly posses you. I believe often times spirits don't move the planchet itself, but it is actually the player's muscles doing it which are actually controlled by the spirit. People say you shouldn't use these kinds of things while under the influence of alcohol or other types of mind altering substances, because a spirit can more easily "attack" you if it wanted.