Their ratings should be a guideline, not a strict ruleset. Games like Call of Duty or even Halo deserve a mature rating but not an 18+ rating. It's dependent on [b]maturity[/b], not physical [b]age[/b]. In the end, the parents know their kids best and should only use the rating as a loose guideline as to what's in the game so they can compare to what their kid can handle.