Blizzard may actually be cracking down on account sharing
Anyone who has been here more than a month knows account sharing is against the ToS/EULA for WoW (and most MMOs for that matter). One of the most public displays of account sharing I've ever seen is top PvP players boosting / carrying toons to high rating. There are several sites out there that will broker the deal to get any character any PvP rank, for a price. Blizzard has stated in the past, paying in game gold for in game boosts is fine. This would be the case where you pay me 1,000 gold and I run arenas with you until you're 2200 (or whatever). This does not make it fine to pay real currency for someone to boost you. What these players were doing was taking real currency and playing other people's characters. You and I know this to be account sharing.
Tuesday a few top rated players found their accounts banned for account sharing violations.
I've known quite a few people that have paid for these services. You've probably seen them as well. Recently I've been spending a lot of time watching various top arena player's stream. They'll openly talk about doing "sells" or carries. I've always wondered why Blizzard seemed to look the other way when it should be relatively easy to find account sharing simply based on IP login history. Maybe they've just now realized that the arena carry business is as large as it is and took action. Impossible to know their reasoning. This wasn't the scourge of the WoW arena world, this was top players. Blizzcon and MLG tournament winners and finalists. These were WoW Arena poster boys. Maybe Blizzard is trying to clean up the image of WoW arena so they can make another venture into E Sports since MLG hasn't seemed interested in Arena tournaments.
I'm not here to discuss whether this is right or wrong. I'm simply wanting to shed light on the issue that for whatever reason Blizzard has taken action against people sharing accounts. A lot of these guys lost day 1 accounts. Let it be a lesson, if you're going to break the rules, be prepared for the consequences.