Privacy issues aside, I assume the main reason for wanting to ship a package anonymously is because there is something inside which could get either the shipper, the receiver, or both, in trouble with the authorities.

So, now you've created an entire chain of people taking that risk! I don't see any reason for a peer to participate in such a network, but I do see a huge reason to avoid participating. Maybe I'm missing something?

Also, I don't know what this has to do with Bitcoin Development and Technical Discussion.