No that can't happen, I don't know why your friend would assume something like that, they only "break" GBA's if you do something that somehow messes with the internal coding which I doubt you or the hacker (talking 'bout the pirate not the person who made Shinygold) could do. I've never played Dark Cry, are you talking about The Legend of Giratina or just Dark Cry?
at least it's only 2 bucks, that's when you should've been able to tell though, most people don't sell stuff like that for 2 bucks. Anyways, shinygolds pretty cool.