> PO Box in profile

Pretty sure government agencies will have no trouble finding you from that bit alone, and then tracking your movements is trivial. I mean, you have to show up and check the box periodically..

They implement a physical Tor each time their check their box - layers of Taskrabbits hiring Taskrabbits. One picks up the Mail and hands it off to the next. The owner is one of the Taskrabbits somewhere in the chain.