[generalizations]

Stuff like what you describe would have lots of artificial seeders, sure - and "they" could even rotate the IP addresses so blacklists don't work.

But it's a big well to poison with such weak tactics, and I think such things have been tried before; and it's not that hard to just...download a different copy.

I usually download a couple different versions of my 'Linux isos' anyway, just in case the audio or the encoding is messed up on one of them. I get that it's fun, and intellectually stimulating, to think about complex solutions to interesting problems, but you still have to look and see if the simple solution is already there. BitTorrent is a robust protocol that's already got built-in mechanisms for these things. The swarm itself attests to the valid files, because those are the files that remain seeded. No need for extra complexity.