With season 4 they enabled Tier dropping against boosted or ebay accounts. While I really find this a good thing I ask myself when you will drop a Tier. I heard that you need the MMR of division 5 below your current Tier (Plat 5 League + Gold 5 MMR + Lose = Drop) and I also have some friends that lost around 15 games in a row (because they have a boosted account) but they didn't drop out of the Tier.
Also when you drop, where will you land? Will you be in Division 1 of your current Tier or will you instantly drop to the Tier where your MMR is?