I like the theory behind the key system, and it works for those who have friends that play pokemon or have both games and two DS'. The whole trying to get people to interact through pokemon thing is nice. I can understand where it would be frustrating for those who can't link with their friends and who don't have the money for both games and such, though. I remember when I was in high school and I couldn't complete a game because of things like that and it drove me nuts. >.<
I think that it would be cool for the opposite key to be given out over wifi.