Wow, I never knew about that. I always hated having std:: everywhere, just so I could have "correct" C++. But I also hated referencing to std implicitly. This is the perfect tradeoff: explicitly state intentions in the beginning, then implicitly reference them as you go. (works until you use eighty five billion lines just to import your symbols)
What is idiomatic is explicitly importing individual symbols into a name peace.
I'm on mobile so please forgive errors.