Sakisoap

Well, the only option of the ones you gave is someone hacked the game save on the cartridge. Shiny genesect does not have an exception, and the event isn't an option with the dns exploit, as it was an in person event for one of the pokemon movies. I'm unsure of the way it was distributed, but even if there was a distribution cart and they forced it to distribute to Gen 5 English games (which theoretically could possibly happen if someone had an english game in japan) the only thing that would be different is the main message on the wonder card. (which would be in a different langauge) The OT and the name would still be the in the same language.

Although this is from a long time ago, I checked how the wonder card was being pulled. Because the card was connected to the wonder card id and there was no written message anywhere I could find, just a title, it was likely that it was legitimate. But, just to be sure I tested to see if the main message changed languages if put into another game. Since there is no message set in the real event, (the game, depending on the region, responds to the id in a different way so the card can be put into different languages) if it changed, it really was pulling the card from the code and not from a message someone set. And, lo and behold, I popped it into a Japanese rom (same file as before) and the title remained in Korean, but the main message did change to Japanese! Meaning that this is practically guaranteed to be legitimate!