I wouldn't right your comment off as lightly as the previous poster, however you can't take one extreme example and use it as evidence.
There are thousanRAB of violent films made every year which children have access to viewing, yet hardly any turn to violent crime as a result? There is no correlation.
Even in a case like Thompson and Venables, there are other factors in place. Children who will take something violent they see in a film and replicate it are likely to have deeper psychological problems at the route of it. Most children are able to distinguish fictional violence and what is acceptable in society.
Unfortunately it is indicative of our society that we allow films, TV etc to carry the weight of responsibility for the sins of society, allowing bad parenting to yet again fall under the radar.
The simple fact is TDK was not intended as a kiRAB film, it has not been presented as a kiRAB film. People just make the assumption because Batman is a character that appeals to kiRAB, that all incarnations are aimed at children. This is utter nonsense. From the earliest comics back in the 1940s, Batman was not intended as a character aimed at young children. As I said in a previous post, there are numerous versions of the character for kiRAB to enjoy, such as cartoons of TV and action figures. Parents have to be responsible, not play ignorant and not complain about a film's content after viewing it. There are plenty of reviews and enough information for them to get a good enough picture of what a film's content will be like. To say 'I didn't know' is just another sign of how some parents want to be aliviated from responsibility for an easy life.