Recently, the Chinese Hearthstone servers drove headfirst into a wall and crashed spectacularly. That however, isn’t the news.
After the rollback occurred (Chinese players lost about 3 days of progress) they found an interesting phenomenon. They opened the exact same rarity of cards in the exact same packs. Obviously, the cards them selves were different, but the rarity remained the same.
If a player opened 5 packs in the three days prior to the reset, and pack 3 contained a legendary. Once the reset happened, and the player opened another 3 packs, the third would again have a legendary, albeit a different one.
The reddit thread has a whole bunch of interesting commentary and a few posts to vods of players opening their packs.
Of course this has other implications if Blizzard is forced to abide by the Chinese law that forces games of chance to show their odds.