An IT exec at a Fortune 100 company once described it as, "With 25K, someone can get into our network. We just need to make than # higher than most of the other companies out there. We can never be 100% sure as long as it's real people involved."
Might be a valid strategy if hackers only had the skills, motivations, and attention span of a grizzly bear.
If the company is a "good citizen", then an approach like that may be justifiable. If you are BP, maybe not so much...