When my shareware was pirated and posted on torrent sites, but had a fairly low number of seeds, I forked transmission and changed the source to give out bad checksums, so that downloaders would never see their downloads complete. I figured I would run this on a bunch of computers and become the top seeds and peers and ensure that few downloads ever finished.

It did not take long for me to realize how crazy I was being over this. My time was better spent improving the software and focusing on customers who would pay.