That would be a smart thing to do. I'm quite sue all payments are handled manually, so someone must have confirmed it on all those wallets.
There should be a rule that all big payments are verified before being sent. It's either an inside job or they were naive and careless.
I don't think everything is being handled manually. If it would, this situation likely wouldn't end up as bad as it did right now. Exchanges processing everything manually would surely help, but people would be complaining constantly as their withdrawals don't come through within a few minutes. I can't find any information on how the hackers managed to move these coins to their own wallets, or how they managed to abuse whatever weak spot in the system. Hacking is a very wide term that in this case may stand for hundreds of ways of how this theft could have happened.
All hacker hacking of financial companies and institutions is not just a matter of course, but with the help of their administration, I am convinced of this. Any secret information that helps to achieve the goal falls into the hands of hackers only from employees.