I suppose the concern was that the could have.As far as I know though they were purist hackers.. Purist hackers merely break into things to say they did.. They don't destroy or profit, its about the challenge.. Granted
The "many eyes" philosophy does apply here. That said, you would think a system that is managing probably the most expensive and potentially dangerous system in the world would be vetted extensively prior to implementation. There are some systems that you just don't expect to be hackable/hacked - this is one of them (I know all systems are hackable at some level).they'll have to scour the system to ensure nothing malicious went down, but on the plus side, whether they find trouble or not, atleast they're now aware of a security hole that could be abused worse in the future..
Dave