Ethereum

Are validators in the same cluster (eg same exchange, same user) more likely than unrelated validators to miss attestations at the same time? If so, can we tweak rewards to favor decentralized staking?

Possibly yes.

https://ethresear.ch/t/supporting-decentralized-staking-through-more-anti-correlation-incentives/19116

Think would make more sense once validator balance limit is lowered & we get closer to stateless proposers. Distributed != decentralized. There's risk of bimodal distribution that pushes supermajority further towards centralized operators. For decentralization, need more distinct operators, not just more distributed