Earlier today Theymos of Bitcointalk revealed that he satisfied a subpoena by prosecutors in the United States related to the yet to be tried Ross Ulbricht case. He offered that he turned over posts related to the account "altoid" alleged to be connected to Ross Ulbricht. He also admitted turning a number of posts, including posts deleted by users from a thread titled "A Heroin Store" which posed and interesting thought experiment:

As a Libertarian, the thing I love most about the Bitcoin project is the chance that it could be truly disruptive.

I think that drug prohibition is one of the most socially harmful things that the US has ever done, and so I would like to do a thought experiment about how a heroin store might operate, accepting Bitcoins, and ending drug prohibition in the process. We'll assume that the drug store is very high profile, and that law enforcement makes discovering the operator a high priority. We'll also assume that heroin is cheap when bought in bulk; the street price reflects the risk that street dealers must take to sell their product.

A drug dealer would set up a website that accepts Bitcoins for heroin. Orders would require a physical address for shipping. When an order comes in, the dealer would send heroin through the mail to two addresses: the address provided, and another random address. Because packages of heroin are now arriving at addresses across the country, receiving a package does not imply that you ordered it. Random addresses would be heavily reused to prevent law enforcement from making a statistical argument.

Now law enforcement could set up such a website as well, in order to discover buyers. So, the drug dealer must take half of his profits (and remember, he's already shipping 2x the amount paid for), and use them to buy heroin at other random websites, on behalf of both his customers and the random addresses that he has used.

If the post office knows that a package contains drugs, then they could send an undercover officer to deliver the mail to your door, or surreptitiously watch your mailbox to see who collects the mail, and then get a warrant to search your house to see if the package has been opened and not discarded. (IIRC, discarded materials are no longer considered in your possession.)

So, it would be important for buyers to not open any package that they suspect may contain their heroin, until they wish to consume it: they would only be in danger of possession between when the package was opened and when the contents was consumed.

Can anyone see a way to attack the store?

Now the setup in question proposes a reverse "Joe Job." In the classical Joe Job attack used by email spammers the recipient is spoofed, but in this heroin reverse Joe Job at least one recipient is spoofed. While the classical Joe Job obscures what person had the Mens Rea to send spam, the heroin store reverse Joe Job would have intended to obscure who had the Mens Rea to order narcotics. The effect is that in a Just system of law a buyer would jettison legal risk for their purchase in exchange for the additional cost in shipping and material. Given a secure messaging system and decent operational security,a refined version of the setup proposed could in a Just legal system offer complete immunity to customers even in the event of perfect interdiction of the product in transit.

Of course in the contemporary United States' injust system practical consequences may occur before legal consequences and the completely innocent recipient can be subject to consequences including the loss of their beloved dogs or even of their own lives.

For people who are skeptical of the timing of Theymos. disclosure for happening so long after discovery in the Ulbricht case should have been completed, the complete text of this post is below:

This is not very surprising/interesting, but I thought I'd mention that I received a subpoena for information related to Ross Ulbricht's alleged forum account altoid. I mostly just compiled some publicly-available information. The only non-public data I had to include were some deleted posts in the heroin store topic that were not written by DPR and probably won't be useful in the case.

You might be surprised to learn that this is the first subpoena I've received for the forum.

Any doubts or evidence to the contrary is very welcome in the comments.