Hasn't really worked out that way.
One problem is that the interpretation of lyrics is subjective, as this FBI investigation so well illustrates. Albums that sound sufficiently pop/clean/bubblegum go without the sticker when there are clearly songs explicitly about sex/drugs/etc.
For an example, look at Third Eye Blind's self-titled, debut album. Semi-Charmed Life is clearly about meth and sex, but it is sufficiently clean sounding that it gets by without a sticker.
Meanwhile, albums that sounds a little edgier, but are actually about clean, mundane subject matter have the sticker forced upon them.
IMO, the movies and games industries have much better, more objective rating systems.
Honestly, the music industry is way better than the movie industry. The MPAA rating system is a literal censorship board, complete with an actual member of the clergy serving in an advisory role on all appeals. But if you don't get your film rated, it's almost impossible to distribute it to anyone but the very small independent movie theaters.
The MPAA results in an immensely chilling effect, which influences the movies people produce in the first place.
Contrast that with music, where the distribution mechanisms are much more varied than for film, and there's nothing preventing people from releasing music with incredibly explicit lyrics, as long as they don't expect the uncensored versions to be played on the radio - a medium which, while still popular, is by no means thr primary distribution channel anymore.
If you believe that, I recommend you watch This Movie Is Not Yet Rated[0].
It's just as bad in movies :-). I don't know anything about game ratings to dispute that part, though.
The original use case was "Darling Nikki" by Prince which, I have to say, isn't a song I'm going to be playing to my daughter anytime soon. (And believe me, I think the whole of Purple Rain is genius.) But the tone? That's hugely damaging. It's all "these musicians are corrupting our kids" and not enough "some people make art for adults and that's OK".
Of course, if the debate had been more reasonable, Eminem would have had to come up with a different marketing angle.
The state forces you to acknowledge its authority before you are allowed to observe and ponder an artistic message - additionally, compromising the display of said artistic message with a big nasty horribly designed stamp of disapproval covering a significant portion of the work.
Its is parents' responsibility to police content their children are exposed to. Its parents' responsibility to read the lyrics of "Louie Louie" and determine if that is safe for their children or not. Requiring the state to burden itself with this role is not only no route to security in such a situation, but tremendously irresponsible of this so-called league of concerned parents.
What do you think I'm talking about with the statement about Walmart?
I guess they make it easier for parents to control some of the circumstances where their children listen to music but I don't see how it affects others.
Worse than government laws about little notifications are things like Walmart demanding watered down versions of the music.