I believe that the system should work but due to the nature of people, it doesn’t completely.
Although I believe to an extent that children must be protected to an extent, the fact that there is no evidence for films causing harm makes me believe that the vulnerable must be protected in other ways.
For example, I don’t believe that somebody would witness criminal activity, drug – taking etc. in a film and then go to do it unless they already had plans to do it in the first place. If anything, society needs to be protected from these people instead of the films that allegedly made them think and act this way.
I do however believe that a young child should not see certain things in case they start to develop concepts such as profanity from an early age but I don’t see why films must be one of the few media that actually has to teach them morality. There are other media; books, art, music that very rarely compromise in a similar way.
