Gates argues that security should be understood as a matter of reducing risk rather than eliminating it completely. By comparing steering-wheel locks and steel vaults, he points out that even strong physical protections can potentially be defeated. The practical objective is therefore to make unauthorised access sufficiently difficult, costly or time-consuming that attacks become less likely to succeed.

The principle applies broadly to security engineering. Protective systems are designed around barriers, detection and resistance, but none can guarantee perfect safety under every circumstance. Effective security consequently depends on recognising vulnerabilities, strengthening weak points and often combining several protective measures rather than relying on a single safeguard. The quote can be used when discussing physical security, computer security or infrastructure protection, particularly where unrealistic expectations of complete protection need to be replaced by a more measured assessment of threats and remaining risk.