Universal opt-in replay protection?

The concept of block height is instrumental in simplifying the transaction verification process within blockchain technology. It is suggested that nodes could benefit from annotating Unspent Transaction Outputs (UTXOs) with the closest block commitment, whether immediate or ancestral. This annotation helps users understand how deep a reorganization would need to be to invalidate a transaction they have received, without altering the traditional security implications of confirmations.

There is a proposition to set limits on how deep new commitments can be made (potentially around the assumed valid height) and the duration for which nodes should track these dependencies. A specific suggestion includes discarding the tracking once the committed block is buried 100 blocks deep. This approach aims to maintain integrity and prevent exploitation through performative commitments to past forks or significant blockchain events, thus ensuring a balance between transparency and security in transaction handling.