With that level of popularity comes some negatives as well. Scammers, thiefs, beggars, cheaters, farmers, crooks, and low life scum. Blizzard has occasionally said goodbye to large groups of accounts, the success of such actions are questionable but at least they are trying. The most recent round of bannings shut down over 18,000 accounts. That is around the total number of people playing EVE Online at any given moment, so it’s not a small amount.
I wonder if banning accounts really slows down the activities that caused the ban. I bet it’s a losing battle for Blizzard. Although, it probably is a financial gain for Blizzard anyway, because most of the banned people will just buy a new box and start over.