you guys are funny. exchanges aren't going to support bip148 because they would be forking themselves from the main chain.
I think smart exchanges are going to list both, because there's a lot of exchange fees to be taken from all people selling bitcoinA for bitcoinB and vice versa.
They've learned their lesson with ETC/ETH.
However, this is going to be one big replay-attack cluster fuck, because the split starts as a soft fork ; it is not going to be easy to separate both types of transactions. Actually, exchanges are in a better position to separate them than individual users are, because exchanges could easily get their hands on coins of coinbase transactions on one prong or another, while individual users can't really, and it is the only way to avoid replays.
Replay protection is not even needed because this is a soft fork,
Soft or hard fork have nothing to do with replay attack. If there are two prongs on the chain, whether it is a bilateral hard fork split, or a minority soft fork split from the main chain, and you want users to "vote in the market", when two coins are listed on exchanges, users must be able to transact one version of the coin, and not transact the other version of the coin. If there's no protection against replay, then every transaction they do on one prong, is also a valid transaction on the other one and will most probably be picked up and included, making the "economic voting" of the user moot: he will not be able to sell one version, and keep the other one.
In other words, without replay protection, there's no room AT ALL for the user in this "user" activated soft fork. The only power the user had, was to vote in the market with his money when miners had already split off, and exchanges listed both coins. But without any replay protection, this is going to be one hell of a fuck-up.
