I knew Runescape had bot problems for many years, but I wasn't aware of the size of the problem. If more than half of their server load came from bots, it is surprising that they didn't write that bot-removal software earlier. There is maybe in lesson in this story that games with a Free2Play business model are more susceptible to bots, because the botters can set up a lot of accounts for free.
On the other hand I've always said that the very best way to prevent botting problems is to make a game which isn't repetitive enough to be played by bots. Everybody wins!