block is created, cooperating miners would choose not to mine on top of it, but start construction of a parallel chain. Where a second consecutive non-cooperating block was created,
cooperating miners would then accept the first non-coop block, but not mine on the second.
Thus If there are 50% cooperating miners, a new non-coop block has a 25% chance of being
risk of permanent chain split * miners free to create block types they prefer with chance they will be included * persisent cost to those enforcing coop blocks if support is low (risk
tl;dr If even a slight risk to miner a block could be dropped then a non-zero contribution is rational. Feather forking like this also fixes difficulty gaming.