It's not about less safe, the C++ defaults are usually just wrong. It's so well known that Phil Nash had to make clear whether he was giving the same talk about

It's not about less safe, the C++ defaults are usually just wrong. It's so well known that Phil Nash had to make clear whether he was giving the same talk about how all the defaults are wrong at CppCon or a different talk, otherwise who knows. For some cases you can make an argument that the right default would have been safer. For mutability, for avoiding deductions, these are both sometimes footguns. But in other cases the right default isn't so much safer as just plain better, the single argument constructors should default to explicit for example, all the functions which qualify as constexpr might as well be constexpr by default, there's no benefit remaining for the contrary. My favourite wrong default is the memory ordering. The default memory ordering in C++ is Sequentially Consistent. This default doesn't seem obviously wrong, what would have been better? Surely we don't want Relaxed? And we can't always mean Release, or Acquire, and in some cases the combination Acquire-Release means nothing, so that's bad too. Thus, how can Sequentially Consistent be the wrong default? Easy - having a default was wrong. All the options were a mistake, the moment the committee voted they'd already fucked up.