There are three things to take from this. 1. Encrypt your address with GPG. It is very possible that the people getting letters were identified because their addresses were sitting in plaintext on the TFM server, or plaintext on the computers of vendors. 2. Vendors, it is vitally important for you to wipe all traces of address information when you are done with it. 3. Get shit sent to boxes that are not connected to you. Fake ID and private mail box is one strategy. People have discussed abandoned buildings, homeless shelters. Less scrupulous people will do a bit of surveillance on a random house to see if the owners are home when the mail comes, get shit shipped to them and intercept the pack before they check their mail. There are a lot of techniques and all have advantages and disadvantages, but here we can see one of the biggest benefits: if shit hits the fan and the feds get an address it will not be your address. The only way they will get you at this point is doing surveillance on the box and watching you pick up. History has shown us time and time again that this doesn't always happen in the case of interceptions, sometimes you get a love letter, sometimes you get a warning letter like this, sometimes the pack just never arrives and a postal inspector knocks on your door a few weeks later, sometimes it says right on the tracking that the feds intercepted your shit! Having an anonymous shipping location is your last layer of defense and in this case we can clearly see that it worked to the advantage of the people doing it, and that not using anonymous shipping locations worked to the disadvantage of the people who didn't use them.