I've once had to bring up my ratio on a (now defunct) private torrent site in orde to download new torrents. I was looking for high leech low seed torrents, and I am ashamed to say I've seeded over 500 GB of granny porn (like 20gb original size). Brought up my ratio, tho.
It is easier to enforce access than to enforce ethical algorithm. Sadly, it is not perfect, but it is better than allowing it.