If he does not check the age-verification now, he will later. Or he'll notice when he wants to buy something.
In general, if you take a Marui and put it right next to the real thing (did it with five real MP5's) you cant tell the difference from a foot away. So I could have a few 9mm rounds sitting there for looks.
Any newbie who whines about wanting a gun will get flamed. Specially if they are 16 or less. Even worse if they dont even want to have their parents involved. Sorry, too young to even try to follow rules that would allow them to play = not mature enough for this game.