Hats off to Tycho for blocking botnets automatically! Remember, it's causing a loss of 3% pool fees.
That's not how I read the screenshot. Look at the account's current hash rate, about 4 GH. So he's letting them get work and submit it, he's likely just made it so it isn't accumulating bitcoins for it - meaning instead of a 3% share of their work he's getting a 100% share of it.