Kids are generally way more resilient than they get credit for, but not all kids are the same. I have two, one of them was fine watching people's faces melting

Kids are generally way more resilient than they get credit for, but not all kids are the same. I have two, one of them was fine watching people's faces melting in Raiders of the lost Ark when he was 6, the other had nightmares for a couple days after seeing Gollum in LoTR. The regulations on age are by necessity arbitrary, but I don't think they're completely stupid, even tho I agree parents should be the one responsible in the end.