a device is a device
A mechanical device is prone to problems that mechanical devices have, just as electrical devices have their own ways of failing. The distinction doesn't pertain to your statement that I objected to.
You envisioned a "single point of failure" that connected all securing devices. My analogy, bad or good, intended to show that only bad engineers design their controls that way. And an electrical engineer would be no more likely to make that mistake than a gunmaker.