Also, to get the packs you need to win against Konami staffs in DL, and I don't doubt there will be a bunch of people lining up for the duels. Getting more than 5 packs is going to take time so long, most of them won't bother lining up twice.
So I'm willing to bet there's just extremely few people who got Sonic Chick from that pack, if there's even any.
Getting the packs is also quite a gamble - if you choose the "hard" difficulty you can get 5 packs if you win, but if you lose you'll get none. If you choose "normal" difficulty, you'll get 1 pack if you lose, but if you win you'll only get 2 packs.
So it's hard to maximize your chance to get the card you want.