You're downloading stuff to your PD cache and sharing that cache with other users. That means you are sending files that other users request and also filling their caches with random data. I would also guess that PD searches the sources of files (search and download) and I don't see how this could be done without prompt (sending data).
If my advice is right it’s only because I’m a good guesser. This also works for the fail part. Guessing is fun
