You are woefully mistaken. The Ouija board itself is inert, with no power of its own. Once a few people have assembled with the INTENT of communicating with spirits, things do happen. I tinkered with those things about forty years ago with stunning results. Remember, the Ouija board is an inert communications device. The force that moves the pointer is the muscles of the participants which are influenced to move through a connection with the spirit. Know this: The spirits who communicate in that manner know what is going on and can increase their power with practice. You do not know what is going on, yet open yourself to their "override" with the same practice.
That turns out to be very bad tactics on the part of the human players.
Yet, the influence goes away when they are blindfolded. Go back through youtube and watch some Amazing Randi documentaries.