I think it's important to note that from a young age people associate a sense of ceremony with watching films. What I mean to say is that when you're a kid, you either watch a film at the cinema, which is quite an event, or you watch it at home which requires use of the TV for about two hours and so has to be (generally speaking) pre-arranged. The effect this has is to cause a lasting dissociation between films and 'real life', if only because of the pre-arranged nature of it all when placed in comparison to the spontanaity of life. And this does not bring into account the important factors of common sense and logic.
Similarly with games, as a child you have no idea how the hell they work - but you do know how to operate them. You have to do this yourself - put the cartridge in, set the TV etc. - so there's very little suspension of disbelief purely because you have engineered the entire scenario in the first place.
But it's irrelevant because if people want to do awful things to each other, it doesn't matter where they get their ideas from, does it? Whether you kill someone based on a fantasy of your own construction or if you do it a la Hannibal Lecter, the net result is identical. The reason that A Clockwork Orange was 'banned' in the UK is because Kubrick himself asked for it to be removed from distribution after some copycat incidents, and the subsequent death threats he received. The irony in that should be clearly apparant; someone does something bad 'inspired' by Kubrick's film, and that in itself acts as 'inspiration' for someone else to channel similar instincts.
I've not added anything to this, or said anything that hasn't really been said already - and I don't have evidence, either - but don't you agree that it's all irrelevant?