I must be an asshole right up there with Necro cause I read the statement "gri gris are COMPLETELY safe. . ." as sounding pretty arrogant, in not a bit ignorant as well.
There's been quite a few people hurt while being belayed using a gri gri. Many people belayed with them and took their hands completely off the rope to take photos, smoke a bowl or whatever. Leader falls, a piece of debris gets swept up into the camo on the rope and the leader decks. I can't think of any time I would use the term "completely safe" to describe any piece of climbing gear, technique or method.
Even sitting on my fat ass posting here is not completely safe.