[ProxCoques]

> the primary principle to follow

Yes. I spend a lot of effort with people at all levels trying to get them to agree on what, fundamentally, the system should achieve for the user. Sometimes it's speed, sometimes entertainment, trust or some other outcome. But that principle needs to be expressed and agreed by those executing the design, if only to prioritise features. I'm always astonished that they seldom want to talk about that, as if it's mindlessly theoretical or something.

> a switch that kills critical [thing] maybe should have a cover over it requiring to flip up the cover then hit the switch; an extra moment of thought.

As an aside, in the digital world a better pattern is usually to have an undo (probably executed as a delayed trigger allowing you to undo it for a time). This allows you to be confident in using the system in the knowledge that if you do something you don't intend, you can just take it back. Not a thing for cars or planes though, I admit.