But showing them something that they're not allowed to be shown is doing the opposite of taking responsibility, it's being irresponsible. It's not their decision to make.
As an example...
Well I certainly reserve the right to be wrong, but that's my gut reaction.
If it was a 16 year old GCSE history student, they shouldn't be shown an 18 cert movie without asking the parents. Christ, is it not possible to teach them about the war without showing a ****ing movie?