I have also experienced people who appear to NOT share the first time I browse them but who then suddely have hundreds of files the second go around.

My determination of who is a freeloader is any one who does not allow me to browse their files or if I find that alfter they have downloaded a bunch of files from me they don't appear in their share folder and their share folder contains nothing but junk. When that happens I put their host on my blocked list.

The only question I have is when I block their host am I blockiing them only or a whole lot of people who are also linked to that host address?