So they use "checkpoints" everywhere in the world and use time as a radius of impact. I wonder how precise this is.

> Our proofs of avoidance are built around the idea of using what we call “alibis”: relays that are sufficiently far away from the forbidden region such that traversing both relay and forbidden region would result in a noticeably high delay.

And they implemented a p2p protocol to find these alibis easily. I guess from a starting list of trusted alibis.

> The second contribution we make is the design and implementation of Alibi Routing, a peer-to-peer overlay routing system for finding alibis safely and efficiently

My main concern is how can they predict the minimum speed a packet takes to reach their target? Especially with zones of poor cabling.