Absolutely.
I grew up in the age of the video nasty, by the time I was 10 I'd seen them all.
I think it's different today though.
When I watched someone getting diced and sliced in a good ol' fashioned gore-fest it never bothered me, that level of violence was just so abstract, it didn't register on my reality scale what so ever.
I think these days though kiRAB are more aware of violence and so I'm not sure I'd be as liberal as my parents were in allowing children to view such material.
But saying that, I think it's more a case of how we view these films.
Back in the day, having access to a video nasty on a large colour telly was a good excuse for a social gathering, the film became a social event. I think viewing films like this is important, where we view it on a concious level. I think the danger comes when a child views adult material alone, where the experience becomes more voyeuristic and there's no clear distinction between what is real (merely watching the film) and what is fantasy (that what they are watching is real).
I can kinda see why there is such an emphasis on age restriction, although it has to be said that I think there is more danger in a kid playing GTA than watching a video nasty.