Quoting myself: last generation (DS games).
The day that encryption on saves is broken (and it's a easier task than finding kernel exploits since savegames most of times use weaker keys and algorithms) competitive play on pokémon games will be plagued by hacked mons again.
Also, the day that gateway gives players RAM editing capabilites (gameshark, action replay like), people can and will cheat at pokémon, editing their mons through RAM, saving the game, using the monsters at online play.
And RAM editing is perfectly doable, I remember those early leaks of pokémons that will be yet distributed at cinemas.