Other posters point out something that I found to be unexpected: The ESRB does not rate mobile games.

Now, yes, the ESRB ratings are not anything to stake your life on, but they do give parents and organizations something to go off. Does the ESRB have massive problems? Yes, of course. Do mobile games need to have some sort of rating system? I'd think that most people would say something would be really nice

Perhaps the ESRB, or an expanded board of a similar nature, should expand their mission to not only rate the content in a mobile game but also should give card-holders a better idea of what the gaming market's financial risks are?