A lot of them seem to be worried that GH/RB sort of plays on and co-opts the drive that teens have to learn an instrument and put together a band. That instead of being inspired to go out and get a real guitar and maybe become a musician himself, the guy who looks at his favorite guitarist and says, 'Cool, I want to do that!' will just pick up GH, jam out with some friends, be satisfied with that, and never progress to forming a garage band or whatever. But even if that is true to some tiny extent (and who can say, really?), it's hugely overshadowed by the number of people who would never have done anything more than listen passively to their music before these games came along.