Erich Schubert wrote about p2p obfuscation/encryption, arguing that it's bad.

Eric, according to some french media (so it is still a rumor for now), at least one french DSL provider (not the leader, the second one) already set up QoS limitation for non-standard ports, prioritizing usage of http/smtp/imap.

Now, customers of this ISP should ask themselves about setting up tunnels on port 80/tcp to route all their traffic outside... :-(