This is not a technical debate: OP_RETURN is a Trojan horse to pave the way for much more profound changes in #Bitcoin BTC

⚠️Spoiler: Bankers behind the scenes

Bitcoin Core v30 plans to remove the 80-byte limit for OP_RETURN as a relay policy, allowing large amounts of arbitrary data to be inserted if the transaction pays.

This move opens the door for many to push that "if we already allow data, let's also allow only 'legitimate' data." This creates moral pressure for filters.

Knots responds by proposing active filters: nodes that do not retransmit transactions with extra data that they consider spam.

There are filtered versions of Luke Dashjr's plans suggesting a hard fork with a multisig committee that reviews transactions and removes illegal data from the blockchain (such as CSAM) using zero-knowledge proofs.

This scheme would imply that part of the blockchain could be retroactively altered at the committee's discretion — breaking immutability.

If nodes begin to filter "illegal" data, the next logical step would be to deploy state filters or KYC on-chain: "legitimate transactions come with identity, the others are filtered out."

Once the notion of filtering data at the node layer is accepted, the leap to filters with regulatory backing is much easier to sell.

In practice, Knots filters only affect the mempool, not already confirmed blocks. A miner can receive transactions directly and bypass those filters.

But if the narrative of "protecting miners from illegal validations" prevails, they would create the argument: "nodes cannot be sure that they are not validating illicit transactions, so it is better to have controls."

We can already see how the debate is becoming political: who defines "illegality," who controls those filters, who has the authority to impose them.

It is no exaggeration to say that what starts as "let's free the data" can turn into "programmatic censorship."