unless someone who works at coinbase reports about their funds we have no way of knowing. so far people who wanted to withdraw have done it and it was completed successfully and with ease. and it is not like their wallet is public knowledge so we can check their balances 
I beg to differ. I found a suspicious and unauthorized withdrawal from my account this weekend. When I filed a request for support they immediately locked my account - to ensure that the security of the account wasn't compromised - I'm still waiting for them to unlock my account and now we're within 24 hours of the deadline to withdrawal if I want the option to participate in BCC.
Fuck. A business like this should be able to prevent shit like this from happening.