The characteristics for this are a little suspicious;
http://bakabt.me/user/186818/powerplay.html...each and every torrent listed have stats that are only a fraction of the actual size.
Of course only half of the stats are visible, so don't know if this pattern is same for the other half.
It could be legitimate, say he preferred to download publicly, but wanted to be notified of swaps etc in the future, he could switch to his own key temporarily to get the system register the torrent in question, and once tracker updated switch back to the public key. Though the sheer number of the torrents would require some major micromanagement...
It could also be that his drive(s) got corrupted, and he used BakaBT to repair the files, but the pattern seems same for recent BakaBT-only uploads as well...