The Swiss cheese model is what people use to sell you more 'security' related software systems that inherently involve more problems. (Also cheese is not very durable, even the kind without holes.)

Swiss cheese applies to more than just security systems.

Hiking with two GPS-capable devices is Swiss cheese.

That is redundancy in my book. I don’t expect holes in my GNSS devices. And if you want to be sure, bring three, because two GNSS units with different readings are not very helpful.

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