From this, it seems like if/when BU is accepted, miners will have to take a leap of faith to mine a block bigger than 1MB (or the currently accepted max block size) and hope that 51% or more of the miners accept it immediately and start mining on it. Otherwise, the majority will reject or delayed-accept that block, which will most likely be abandoned and their block reward lost."Bitcoin Unlimited makes the process easier by providing a configurable option for the accepted and generated blocksize via a GUI menu. Bitcoin Unlimited further provides a user-configurable failsafe setting allowing you to accept a block larger than your maximum accepted blocksize if it reaches a certain number of blocks deep in the chain." - https://www.bitcoinunlimited.info/
On the flip-side, when a miner is configured to reject or delayed-accept a block that the majority of miners accept, whenever such a block arises that miner will most likely follow old blocks and abandoned chains until their failsafe hits, and in the meantime all that work will be for naught.
To address this, is there a mechanism for publishing your current blocksize settings to the blockchain when you mine a block? The most critical piece of data to include is the maximum block size that each miner will immediately accept. That would take the guesswork out of when it is safe for miners to increase their generated blocksize, and will give them helpful information about when to modify their configured settings to avoid lost work.
For example, if the current blocksize limit is 1MB and 2/3 of the last 2016 blocks are mined by miners that have announced on the blockchain that they will immediately accept a 2MB generated block or higher, then miners are relatively safe mining up to 2MB blocks, and miners who will reject or delayed-accept blocks over 1MB blocks are at risk. However, this would be for information purposes only, so the decision regarding when to actually start generating larger blocks or change configuration options would be left up to each individual miner.
My apologies if this is a duplicate, I looked through the BUIPs and forum posts but didn't see this.