The thing about Pokemon fakes, is its not hard to spot. All you need to do is look up a list of official releases and how to label art looks. Usually if the Nintendo logo is there, and its a officially released title, its real. Example, Pokemon Dark Cry for the GBA. DArk Cry is on no official Nintendo release page at all. That's a fake. I've never seen an instance where Pokemon Crystal for the Game Boy Color was fake. You can tell the real thing.
My main concern is the high end games. Does anyone know how to spot a real and fake Flintstones copy for the NES? And Halloween for the Atari 2600?