The manual for my cordless jug tells me I must switch off the power lever before lifting it from its cradle. It doesn’t tell me why. When I lift it off, the lever actually returns itself to zero automatically. What might happen if I do it “wrong”, how bad is it, and how likely? Some engineer knows somewhere.
When Aunt Magda comes to visit and decides to make tea, will she perform this step? Highly unlikely. I guess I’m supposed to tell everyone who uses the jug, or request they read the manual. Heaven forbid someone buys it second-hand without the manual, or just doesn’t read it. I’ve lifted it without switching the level off once or twice; if something terrible happened I didn’t notice. Maybe missiles were launched in China.
I have no information to go on for how important this is, and it’s a theme I see everywhere. Use and maintenance information in the official literature is often overly strict and thorough – seemingly designed to remove all liability and responsibility from the maker, not to mention sometimes wrong or applying to some subtly different product.
We have a problem as a society with not explaining why, from maths teachers to superstition. This is just one symptom of that problem.