interesting bit of info re: possession

There are some Christian faiths (my own) that believe demonic possession can only occur if and when a person allows it. In other words, a demon can't just randomly possess a person because it feels like it. It can't physically force a person to do something, and it can't physically affect a person. Its power comes from its ability to lie and deceive, and in the art of suggestion and temptation.
A person can become possessed in a number of ways:
- participation in demon worship
- participating in evil activities in general, thereby weakening their defences against evil and finally succumbing to it
- under hypnosis, where the mind detaches it self and becomes open to all sorts of suggestion and influence
- etc
I guess it all comes down to the concept of Free will. A person chooses their own path.
This was not addressed in this film, in fact I have never seen it addressed in any Hollywood film