I can remember when I could see, most instruction books for home mains operated audio gear had a little picture. A strangely short squat man holding an umbrella with very large raindrops dropping out of the sky, a stylised cat sitting on top of the piece of equipment on a table and a bonfire next to it with a red line through it.This I suppose meant do not use outdoors in the rain wallow your pet to lay over the cooling vents or expose to excessive heat. I did not get the thing about the umbrella though, unless some Far eastern equipment had some strange aversion to these devices or they were subliminally trying to sell you one.
Do books still contain such things, I suppose these days they may need one for does not contain nuts or use in the bath as well. Brian