Also leaving Alts on Exchanges is the same as leaving BTC there since when you come to sell back into BTC your leaving it up to a third party to choose between BTC and BCC . . . or whichever chain . . .
Am I right?
You are right so don't just leave altcoins on btc exchanges. I'd rather sell now all of my altcoin stash rather than leaving them on exchange. My course of action tough is to sell some alts and hold some on a wallet that I have complete control with, or ones I own a private key. Even alts will be affected on august 1 if there will be a split so its better to prepare for it now, decide what to sell and what to hold.
better to download wallets where you have full access instead of leaving it from the exchange even though its bitcoin which will be affected
its still better to be safe than sorry after, its a decision that you really needed to research and learn deeper.
Consider on using wallet where you can monitor the price so you could decide on whether you are going to sell or buy Bitcoin. In terms of altcoin we can see that it's price is aligned to the price of Bitcoin so if you will monitor the price of Bitcoin that is also the same on monitoring the price of altcoin it self. Just take time on having trading site where every altcoin have price in terms of Bitcoin. Do not be affaraid on having altcoin and Bitcoin at the same time holding because it may lessen the risk in you investments and transaction.