It was the only shiny on the card and he had a lot of average pokemon, so that's why I'm assuming it wasn't some hacker. The only shiny pokemon I've every found through all my playthroughs were a zubat, sandslash, and a parasect. I caught the first two and the parasect was in the safari zone so ran away despite my best efforts to coax him in.

My latest playthrough on diamond has a pretty epic team because I'm trading all my best pokemon from every game into that game (although only using the ones of an appropriate level at that point in the game). My Aerodactyl (which happens to be the best nature for him, which is adamment) is able to basically take any pokemon down with one or two swipes of his wings no matter if it's super effective or not (usually taking them down to a sliver on the first hit). It's like I ev trained him or something. He's only level 25 and I have great faith in him (err...her. Actually, all my main team happens to be female at the moment.) She might be so good I'll give her a vacation for a bit.