Earlier quoted context omitted.
Indirect networking much like Tor or I2P. Translated to BitTorrent, everyone would be using just one extra hop to keep the speeds up but passing around encrypted packages for others would create plausible deniability. You can claim you don't know what the packet that you routed contained, because you can't know that. You can't be held liable for routing traffic per se, much like ISPs aren't liable for routing traffic…
Unless, of course, the authorities seed Tor with a whole bunch of nodes that log everything. No timing attacks required. Tor relies on the fact that even if there's one or two bad apples among the bunch logging everything you're probably going to be safe because you'll go through enough routing nodes that aren't logged for it to be impossible to trace.
If all you can see is routing you can't know where packets originate or are destined to. You receive a packet, open your layer of encryption, see where the packet should be going next, log it, and send it forward. You can't possibly know whether the sender created the packet or forwarded it, and you can't possibly know whether the recipient consumed the packet or forwarded it.
You would need to monitor physical network links to determine patterns how the onion style packets travel around.