Then send the BTC to another address and make the following announcement:
"We got hacked. 3900 BTC were stolen from our wallets."
It's easy … isn't it?
thats a great idea but risky too.....giving the statements "we got hacked" must not turn into " you are the hacker"
In order to achieved that kind of shit method you need at least 5,000btc to cover all the transactions made in your exchange site. You will spend for security, domain, developers, admins, advertising etc. You also need to registered your site. You will face lawsuits here.
Why bother do that kind of shit method.