There should only be 4 rating systems:
[K] - KIDS. Kids can see this movie. It has no actual plot, is filled with inane chatter, and has pretty colors. Movies like Spongebob, Hannah Montana and Star Trek Nemesis fall in this category.
[NK] - NOT FOR KIDS. This rating means there will be explicit sex, gore, violence and everything else that makes adults ditch their kids at a babysitter for several hours. Movies like this include SAW, Brokeback Mountain, and Curious George.
[NBK] - NOT FOR BLIND KIDS. This movie may have visuals that are safe, but the audio is disturbing, deficient or lacking in descriptive supplement. This includes movies such as Silent Movie, Wall*E, and just about everything by Michael Bay.
[NFA] - NOT FOR ANYONE. Any movie by Kirk Cameron.
J.