Very good analogy, very well put! And yes, layers of automated security are the first and best protection.

In addition (not instead of): We have to understand that, even with the best security layers, bad guys will on rare occasions get through. So its good to have people inside, checking all the pathways, looking for the unusual. People who can say "Wait a minute, these guys with guns don't look appropriate. They should be at the party, with drinks in their hands. Not clustered around the vault, with guns."

And then a sufficient number of bullet-proof heroes to isolate them and neutralize them. Rather than just one McCain without a bullet proof vest, and without a lot of backup.

Because in the movie, the moral of the story was
(a) Always have a good guy on the inside.
(b) One good guy may not always be enough. (In the movie, he got lucky :-) ).