This kind of thing is even worse news for anyone who cares about Events and can't get to them personally. These
Celebi are being offered in the Trade Forum here on Bulbagarden, and who knows how many other places.
The fact that they are hacked will get lost in the noise as the people who trade for them now probably won't remember to remind people they are not legitimate at a later date.
No, these kinds of things aren't going to hurt anyone's game. It's just more garbage anyone who wants Pokemon from people who actually play the games will have to sift through.
Bookmarks