I guess what you think is true. But most of the exchanges have said that if there will be two coins or a split will occur they will support bcc or bch and they also said all btc in the exchange will be automatically be called bcc or bch. But there is an option there since they said that we can exchange or trade BCC or BCH to btc if we dont like it inside the exchange itself. I dont know in the case of bitfinex but that is how I see how the exchanges will settle things when a split will occur. But I hope that during the split we can have both coins and we can earn both from their value, if this is the case then I pray for a split but if we cannot have both coins at the same time together with the value I wish that the split will not occur.