I just hate that concept (and it's not just CBA, to be fair) of 'oh something happened, we can't do anything until the next business day'
it's complete bullshit, and if you argue it you can pretty much always get it reversed - they're just using your money for one more day of trading. it doesn't cost them any extra for your excess withdrawal (or intra-bank transfers etc) - they're just using that money and your thirty bucks along with shitloads of other people who made a mistake about how much was left in their account to have another gazillion dollars to trade on the markets to make profits we never see, or losses we feel in increased fees!
fuckers!