Knowing the basics of operator precedence should be expected. If you don't know it, you don't really know the language. I don't see any validity in a compariso

Knowing the basics of operator precedence should be expected. If you don't know it, you don't really know the language. I don't see any validity in a comparison to knowledge of the standard library, or of variable scoping. Ignorance of those aspects of the language has very real, measurable costs. Using unnecessary parentheses incurs no cost at all unless taken to an extreme like some of the examples posted above.