However can you still post a signed message with your BTC wallet to provide you have sufficient funds to cover periods of losses against your website.
Even having a low max bet isn't enough proof since you can have like 1 BTC in your wallet and with enough gamblers that will be used up quickly.
Yes I agree with you, OP should provide cold wallet address and sign a message with that address so that we can be sure all withdrawals and winning will be processed without any drama in future, till than its better to not deposit anything in the site.