[tor-relays] Request for Tor abuse complaints - Question regarding Bittorrent

[janulrich]

Sadia Afroz:
> We are researchers from Univ. of California, Berkeley and Univ. of Massachusetts Amherst are interested in understanding what kind of abuse happens through Tor.  Thanks to Moritz Bartl from Torservers.net <http://torservers.net/> we analyzed over 1GB of complaints received over 6 years.
> Here is our preliminary analysis of the complaints:  http://www1.icsi.berkeley.edu/~sadia/tor_abuse_complaints.pdf <http://www1.icsi.berkeley.edu/~sadia/tor_abuse_complaints.pdf>

Quote from paper:
> 99% are DMCA complaints regarding the use of bittorrent.

Why do these complaints go to the exit node operators?
Isn't the complainer able to figure out the real IP of Bittorrent clients?

Why I am asking this: torrent uses UDP, Tor only routes TCP traffic.
Isn't it impossible to hide bittorrent traffic via Tor.