Blackrock filed for an amendment to its ETF:

“Subject to confirmation of the foregoing required minimum balance, Coinbase Custody shall process a withdrawal of Digital Assets from the Custodial Account to a public blockchain address within 12 hours of obtaining an Instruction from Client or Client’s Authorized Representatives.”

So, Blackrock didn't anticipate a need for this from the get-go? Maybe we really should be asking "What's going on with Blackrock?"

https://cointelegraph.com/news/blackrock-bitcoin-etf-amendment-coinbase