No nice things
So my experiment with bittorrent here has ended before it even started. I was running transmission-daemon as the seeder - but apart from a couple of short tests only had it running with no torrents being seeded.
Despite that i'm getting 500MB+ traffic PER DAY! just from peer requests (I guess, as there seems to be no way to find out what's going on inside transmission).
And the thing is I never publically released the torrent files it was seeding so some port scraper has done it and added it to some peer exchange. Despite blocking the port i'm still getting dozens of incoming packets per minute but I guess they'll quieten down over time.
Fortunately I don't pay for traffic.