Twitter must recognize patterns associated with bot accounts and purchased followers. Why aren't the bots shut down, or some other penalty imposed upon those accounts which exhibit certain behaviors described in the post?
It sounds like the bots pose more of a problem to Klout & Bing than they do to Twitter. Everyone's Twitter feed ("core functionality") still works very well even in the presence of this type of not, but the same cannot be said of the effect they might have on the core functionality of Klout and Bing.
Because that's not as simple as you make it out to be, the bot creators will just make the bots look more real, then you create an even bigger problem. Bots that function like real accounts. It wouldn't be hard to do at all it would just take some time.
