One of the most basic of security principles is the 'need to know'.
Utter BS... Security by obscurity is very bad practice, regardless of the field. The only security that works is when issues are discussed and taken care of.
As for the heist I certainly agree that breaching the perimeter fence is something that could happen almost anywhere - no need to hide it from public forums either. The whole question is how they managed to get away undisturbed