Prevent other users from downloading partial files.
There are some files that I download that I don't want to share while they are still partial files. For example - Adult Content files. Until I know what is in the file I don't want my computer to allow otheres to download it from me. If I download objectionable content to me I delete it immediately. I don't want to share objectionable material with anyone until I decide to do so.
this would defeat the purpose of torrents. you download a bit, you share a bit. If everyone just downloads and doesnt share then there would be no seeds...
maybe u shouldn't download **** then if u find it objectionable
btw you can preview video files even partially downloaded with vlc..usually