If you want to be sure those MAFIAA misfits never latch onto you, disable
sharing your downloads folder and also partial file sharing. That way, you will
never share anything that you downloaded until you choose to do so on purpose.

Sharing the download folder is controlled in Tools/Options/Sharing (remove it
from the list and uncheck "Share finished downloads") and partial file sharing is
in Tools/Options/Uploads. Do those and you're practically bulletproof because
they won't be able to see you at all.