If you watched that video, then you know that there is danger afoot. To summarize, do not save your game in Lumiose City. It can corrupt your save file and you will be forced to start over your entire game. Seeing as how X and Y may have the most in-game content that we have seen in a Pokémon game, that is not good. Basically, they can patch the game through a system update to correct this issue, but you should play it safe until that happens. As far as I can tell, this can happen in both X and Y and it has been happening across various regions. Even more reason to simply play it safe. So, save as often as possible when you are near Lumiose City because you don;t want to be stuck there and need to save. Unfortunately, this is a pretty big issue. Losing your save file sucks and I know that I would probably grab a hammer myself if that happened to me. Oh well, I will update the site if and when a patch to fix this issue is given out. Good luck with the new Pokémon.