Right - and this gets to perhaps the stickiest point on this: is a node a Sybil if they are the most efficient route into the network? If a single node can make all the blocks, they still only hurt themselves by adding hops (reducing block time, opening door for someone else to do it faster).
Many people argue that because nodes can still create an arbitrary number of identities, that they are in fact Sybilling. I believe that is incorrect, and [Wikipedia](https://en.wikipedia.org/wiki/Sybil_attack) seems to agree:
"[A Sybil Attack] is an attack wherein a reputation system is subverted by creating multiple identities"
If you take 'reputation system' generally to mean a system where nodes are gaining power from their identity, or in the case of Saito: their behavior, then you can easily say Saito is Sybil Proof even if it allows arbitrary identities because the 'reputation' you use to influence the network cannot be gamed by making additional identities - even though making them is free.
