Blizzard is going very scummy with their promotions all of a sudden. They did a sort of pyramid scheme for Hearthstone not that long ago. "Bring a friend and you get a pack"
How about...listen here, this is some groundbreaking stuff here: Not giving them attention at all? Don't go to official sites ever, I get all my source on cards from hearthpwn that way I can just cut through all the bullshit and view it whenever.
Nexon's doing something similar with the 5th job release for Maplestory, but participation isn't mandatory (sharing the stuff just gets you extra prizes). I think the technique became popular because it's free advertising for something people normally do anyway (sharing to social media).
"The point being to not mess up with Blizzard's progress bars."
Or don't bother. Some people on Reddit were saying they were clicking the button for 3+ hours thru incognito mode... seriously? You're going to waste your life pushing a button to get a card reveal a few days earlier?