So with
all this raging debate - punctuated by tasty price spikes of volatility everytime a dev makes a new viral blog post <3 - what's going to happen if there is indeed a fork..?
Will BitFinex suddenly rush to list
two BTCUSD instruments - one based on Core/SegWit, the other on BitcoinClassic/GA+JG..??
I presume at first, the BTCUSD we've always traded since ~2012 is just gonna continue to reflect Bitcoin Core's price, not other versions - even in the event that other versions actually get 75-90%+ voting+adoption majority..?
What are you talking about? I don't see two BTCUSD, one Core on Classic...

Unless you are trolling...
He probably speaks about this thread:
https://bt.irlbtc.com/view/1342268It seems like technically a fork will happen with segwit. One chain with segwit nodes, only they know the segwit transactions and one chain with the old nodes, that don't understand segwit transactions.
In general, i would not trust segwit transactions that i receive as an escrow or personally because what happens when segwit loses against the old nodes? Then these transactions are transactions in an abandoned fork. Maybe when segwit wins >50%, ok, but i think it's risky to believe that it really will win.
On the other hand, when segwit wins and coins that are moved on segwit already were spent later on the normal chain then you still might lose coins.
It's really no fun. The problem is that this soft fork is different than those from before. Check out the thread to find out more.