mintpal and cryptsy have confirmed that they are aware of us forking and will be prepared.

to be %100 safe you should always be in control of your own coins.

not to spread fear, if you have no other options but leave your coin in the exchange then you should be okay too.

if you have no means to sell/trade your coins anytime soon my personal advice would be to move your coins in your wallet anytime a hard fork is being executed

cheers

-Who