Your level of involvement is that you stare at it with your mouth open. You can turn it off or change the channel, but other than that its not interactive. Broadcasters have to get a complicated and expensive license from the FCC in order to be able to push this information at you. If the government says they have to start rating their programs and encoding the rating into the signal, they will comply or face losing their license to make money. TV set manufacturers must also meet standards.
Lets look at it.
First, you'll have to require ALL Internet web sites to have a rating. No, I don't think you can assume we can make people in the rest of the world put electronic ratings on their websites. And I don't believe you can claim to be the most freedom-loving country in the world while blocking certain web sites from our data networks. Filtering software already exists, and mostly works. People who are concerned about it should use it.