Can you please show the bitcoin address/addresses where the your bankroll is being held?
Its as simple as posting a bitcoin address with some bitcoins in it and posting a signed message along with it.
No. I signed a message from an address with around .5 BTC, it is a part of our hot wallet.
I have more than one cold wallet - there are no amounts over 5 BTC on one. I do not want to get the private keys of these addresses. Then they are insecure and I have to generate all again - the private keys are protected with the same password.
Can't you even care to get the private keys of few of the addresses holding 5BTC? If you do this, I am sure people would feel more safe to play on your website. Its good for your business and if you are denying to sign a message with cold wallet addresses then surely there is something fishy about it.