Proposed (incomplete) spec:
— The new name is «Zcash Emergency Mode».
— Coinbase only mode: drop mempool txns, everytime tx comes to p2p drop it
— Activation is a «soft fork»-style at a well-known height.
— Implemented as a config option that takes the height, so that for activation we can tweet instructions. *Danger:* What about spoofers tricking victims into enabling it?