Hard nut to crack.
I do agree that people who are rating any type of media should experience it in its whole.
It is the government’s duty to 'protect' the users (us) from getting content we don't want/was not expecting. This is an important issue and as such resources should be invested to set up a team that can, for example, play a game to its full length.
This should result in an appropriate rating with enough scales to describe the content of your purchase.
These ratings should then be enforced to the stores and fined if broken.
Of course this will not solve current problems but its always a good start.
Banning, in my opinion is not an option and goes against individual rights. As long as it is marked and you know what you are buying nothing should be banned.