The concept is mostly what parents want for their children. Every parent is different. Some have no problem taking a 10 year old to an "R" rated movie, others would not dream of it.

Anyone who has had young children will tell you that they can definitely get very freaked out by violent or "scary" movies and most parents do not want to expose their young children to explicit sexual content either.

I have no problem with mandatory labeling of violent or sexual content in movies or music. It helps me make decisions and it doesn't deprive adult consumers of anything.