That is a very creepy concept. No one is ever safe. You can't be a good person, outsmart, perform an exorcism, or do your research and give the thing what it wants. You're going to die.
I forgot all about Grudge 3. I think that's the one where it just randomly has the kid and Kayako's giant head (her eye is a big as the door) looking out of the house in one scene.