Great news for everyone who's selling their votes via smartsteem! A long awaited update has finally dropped! You can now individually blacklist users and tags from being able to purchase your vote!
I, personally, have been waiting for this for quite some time. A lot of my votes sell when my VP is idle and above 99%, so sometimes my vote sells to some people who abuse the system and are only churning services like this in order to game the system. I hate that!
Now, when I discover that my accounts has voted on something unsavory, I can simply ban them from my services with ease. Doing this is super easy.
All you have to do is first click "Settings."
Then go on to click "Vote-Selling."
Scroll down a bit to the section "Blacklist," and then type in the user you'd like to prevent from buying your vote in the "New User," field. Then click "Add User." As you can see, I've already blacklisted an abuser, 
To prevent a specific tag from being promoted with your account, you can add specific tags in the "New Tag," field and then by clicking "Add Tag."
Once you're all done cleaning house, be sure to hit the save button.
