And that can be mitigated with Tor over Tor, or persistent layered guards, but you don't know and can't trust what the hidden service operator is doing. Well yeah. Silk Road exists because of LE incompetence / not caring in more ways than one. If they cracked down on shipping, the market would be gone, but 99% of packages get through the mail. They don't have the resources or don't care enough to crack down on everything, and that's part of our threat model.