MEV burn: Incentivizing earlier bidding in "a simple design"

How do the attesters come to a consensus on what the mev-burn basefee floor is?

Are they only attesting if the block has a greater burn than what they locally think the basefee floor should be? Or does Attester 1 need to be able to verify that Attester 2 voted correctly?

If its a local comparison, then how does the proposer then know how much MEV actually needs to be burned for the block to become canonical? Presumably the builder/proposer will want to cut it close and only burn as much as is required, but no more. This could lead to many blocks not making the threshold when there is uncertainty around what it actually is due to a flurry of bids at the threshold deadline.