varanus_komodoensis
they call me Varanus
This isn't actually true. Hacking a game can't magically make stuff appear that doesn't otherwise exist within the game. Yes, you can get Pokemn with illegal abilities. But you can't MAKE UP YOUR OWN ABILITY and give it to a Pokemon. In a similar fashion, if a Pokemon didn't have a shiny sprite programmed into the game, there'd be nothing to hack. It'd be a code that did nothing. Might freeze the game but power off and back on and all would be fine.
That being said, I'd guess (I'm not a game researcher myself so this is just theory) that a Pokemon's data structure REQUIRES a shiny sprite as part of it.
That's a good point. I don't know much about hacking the DS games - my knowledge of hacking hallows back to the days of Red and Blue, when screwing around with the coding and trying to create something that doesn't exist would REALLY bug up your game and make strange and funny things happen, and sometimes render it completely unplayable. I have no idea if that's how it works with DS games (I assume it doesn't do that, according to what you said). I was just theorizing.
I also think that you're probably right about the data structure - I would also be willing to bet that the game requires a shiny sprite for every Pokémon.