This is a very nice and easy explainer of three possible scenarios of what happens in bitcoin the next few days.
Scenario 1: (almost) no miners signal
If current miner signaling is any indication, this is the scenario to expect.
From the perspective of anyone running Bitcoin Core or other non-BIP110 enforcing nodes and wallets (the vast majority of the Bitcoin ecosystem) blocks will be mined as usual, and transactions will be processed like normal too. Anyone who’s not actively tracking these events on social media or elsewhere may not even be aware that anything unusual is going on, and in a practical sense for them there really won’t be; BIP110 does not affect them.
The same is not true for anyone running Bitcoin Knots or other BIP110-enforcing nodes, however. Since their software will reject non-signaling blocks, they basically wouldn’t see any new blocks at all (or perhaps a few per week), and incoming and outgoing transactions won’t confirm (or incredibly slow). In practical terms, these nodes would stall and become unusable.
If this happens, BIP110 proponents will have to decide between waiting to see if things improve for them (see scenario 3), giving up (switching back to non-BIP110 software), or deploying a next protocol change, like hard forking to a different proof-of-work mining algorithm.
The only thing that I'd add to Scenario 3 is that a signaling fork around 50% (with, say, 20% margin on either side) is not something that has to be a permanent split. It can cause chaos.
I still think it unlikely to go that way, but there's no place for banter, egos, arrogance or any other form of self-deceit in risk assessments, so can't exclude the option. Just can assign a likelihood of it happening, the impact of it happening, and what mitigations can be set up.
I'm personally ready for tomorrow.
Nit: wipeout occurs of course when the total work of one chaintip exceeds the other, not when it is longer.