Need to block blockers

I get the occasional visitor who has me blocked and isn't a follower. I am unable to block them at their blog because I get a "this blog doesn't exist" screen (when it clearly DOES, according to the other indicators I see), so there's no way to block them there, either. 

If it is possible, I would suggest copying the circle with the line through it feature in "Followers" to "Activity" in order to make it simple to stop these snipers from picking on my blog while being protected. I've noticed that these wiseguys usually get around being blocked by just creating other accounts with similar names, so such a feature would make it simpler to thwart them.