Copyright agencies that monitor torrents here have actually verified that peers offer at least one offending chunk on protocol level and the Market Court has decided it's the minimum that can be considered sharing. As far as I know, nobody has yet claimed their client has been modified to download without seeding.
I wrote a modified torrent client that fake seeds. No data (not even a byte) of the content itself is ever uploaded to another peer.
I'm aware this is an asshole move, but it made the lawyers happier.
I've genuinely been wondering if someone building these models has done exactly that, precisely after discussing with lawyers. It seems like the obvious move, legally.