I keep on telling people who cares to know, DO NOT ever leave your coins on any exchange. No matter how secure they claim to be, or promise to be, they can never guarantee you that their exchange won't be hacked anytime. Do yourself a huge favor and open a secured offline wallet for storing your coins. When an exchange gets hacked, it is only an apology that you will get from them, not a single coin.
Yes it sounds reasonable. But as far as I know allmost all exchanges that were hacked compensated the lost fund to their traders. Especially if we talk about top exchanges, they have a huge daily income and there reputation is much important to them that some stolen millions of dollars. I don't mean to say that is very safe to store your coins on an exchange but in most cases I won't hold my tokens in a wallet, I prefer to set a sell oder at the desired price and wait until it's sold.