I am glad to hear that most theaters do not enforce the movie ratings system all too consistently because the system is much too general.
What is it about the magic age of 17 that makes kids all of a sudden ready to see R-rated movies? The fact is that most of us can handle these movies (without being corrupted) long before then, because our parents have taught us the difference between real life and celluloid.
I do not believe that a movie theater should decide who can and cannot see a certain film according to a person's age.
One more thing: Why do theaters that enforce the ratings system still charge adult rates to children who can't see adult movies?