What I suspect will happen is that we'll eventually get a block larger than 1 MB in the blockchain and Core will adapt their codebase to permit its users track the most-work chain. In other words, there will likely be no split--just an anticlimactic network upgrade to larger blocks. In such a case, who wins the bet? Or is the bet only valid in the case where there is a persistent split?
It's absurd to think that there is not a
single miner who will continue operating under the old network rules -- and that's all that it takes to create a persistent split.
It's seemingly this very lack of critical thought that leads to BU not being able to make even minor changes to the client without introducing bugs and vulnerabilities.
Alright: how about a small side bet for us little fish? I bet you 1 BTC that--should the most-work blockchain include a single block larger than 1 MB--that no minority chain will make it beyond 2100 blocks (~2 weeks and the length of a difficulty adjustment) without either a difficulty reset or a change in the proof-of-work algorithm. If I win, the 2 BTCs in escrow will be sent to me. If you win, the 2 BTCs on both chains will be sent to you. If nothing happens by December 31, 2017, we both get our 1 BTC back.