Comment by hellojesus

It's as easy as parents keeping the default router password, a kid logging in and then setting up port forwarding to a device on a port that they're running a server on, tied to their current residential ip, and then pinging their friends that ip and allowing them all to connect and download whatever files or upload whatever files. The peer-to-peer network could really start establishing itself in ephemeral and very hard to track ways. All you need is one kid with access to a vpn to torrent without copyright concerns to seed the network. Or one kid to get its parents to buy a domain and use that as an anchor so that the dns to ip is set behind the scenes for the peers.