I've been a WinMX user for years before their intimely demise, and the MXMonitor was my favorite tool. It ensured a fair trading environment. My favorite feature was setting the minimum number of a user's shared files.
Too often I'd see people sharing tiny .db/txt files from their iTunes folder, or a bunch of random jpg files just to bypass the 0-shares-block. I'm currently sharing 17gb of music, and someone just tried to download a whole album of mine with his shares consisting only of tiny files from inside his iTunes folder.
I'm a reasonable guy, I don't demand that users thank me for every file they get from me, or say things like "share 1000+ files or get banned", like I've seen a few people do. Not everyone has 1000 files to share.
But I don't like freeloaders.And users that have junk files in their sharing folder to create the illusion of sharing obviously know how to share files, which makes it clear that they don't intend to share anything. And I should have the option of blocking them from downloading from me.
I don't see an option to block a certain user from downloading from me either, even though I see it referenced just about everywhere. Just the usual "ignore" option that only keeps them from talking to you.