Report her thread. Thats scamming.
No it's not. If she was selling it stating that the Normal Gem turned into the Mega Stone when traded, and because of that, stated that the price would be increased, then yes, it's scamming. But from what I saw in the thread, it doesn't say anything about that, so it's just spreading false information, handing out a free Normal Gem at no extra cost.
I mean, I haven't had the Diancie event, so for all I know, when it's traded over it could change into the mega stone (could say on the wonder card or sth), but I've seen the event, and there's nothing saying the Normal Gem turns into the mega stone, and if it did, I'd assume it'd appear on Serebii/Pokebeach, which it isn't - so no, I don't think it's true.
But at the same time, I don't see why it matters. I mean, wouldn't you rather take the chance of getting the Normal Gem, with the slight possibility of it turning into Diancie's mega stone when traded to ORAS, and if it doesn't happen, hey, at least you got a free Normal Gem AND the mega stone, then not getting the Normal Gem only to find out you need it to get Diancie's mega stone, and basically you're ****ed because you don't have a Normal Gem. It's really not hurting anyone.
If anything, she's the one "scamming" herself out of a Normal Gem that she could have kept for herself and sold separately for more TBT bells lol.
I don't know if anyone has mentioned this yet, but there is going to be a Dual Pack (North America only) for Omega Ruby and Alpha Sapphire. Nothing is really special compared to the standard release. The price for it is the same as it would be buying the games separately. The only difference is that you get a code for 200 free Potions, thats 100 for each game
Anyway, on topic. I don't think it's been said here, but Japan's getting a shiny Jirachi event. Probably won't get localized so lol