Right. That's policy routing. You can talk to an ISP, have a cable installed and a peering session, gain trust, offer cheap or free traffic delivery, and then publish a route via that session. Your trusting peer may/will then send traffic to that route via you.
This happens legitimately, e.g. when an end-user becomes multihomed or starts using anycast, so the trusting peer can't necessarily discover this algorithmically. Route signing helps.
This happens legitimately, e.g. when an end-user becomes multihomed or starts using anycast, so the trusting peer can't necessarily discover this algorithmically. Route signing helps.