I'm not quite proposing the exact situation that they had, but I am suggesting that adding more layers of physical security might not be the solution. And if indeed this was really a case of insurance fraud rather than a straight theft, perhaps the outcome was good for everyone except for the insurance company. To the extent that the vault was good enough for them to obtain insurance, the vault was good enough.

To obtain better security, the motivation of the participants needs to be analyzed. Perhaps this is a problem best solved through obscurity, with two competing security teams installing two totally separate alarms systems, each standing to lose if their alarm is defeated. Or perhaps skip the alarms, and rely on threats of deadly force.

But although any new insurer will properly demand the technological improvements illustrated here, it would be foolish to believe that technology alone will keep out a dedicated team of insiders with full access to the system. Real world security is not equivalent to public key encryption where security can be established by 'proof'.