Currently in some (well, unfortunately many) languages. C++ references have always been non-nullable, and in Scala the only way you should get nulls is from Java libraries.
With option types, we check whether it is empty once, and if it is not, we unwrap it and use it as if it were never nullable. Any function that uses the unwrapped value downstream is oblivious to the fact.
But they provide a useful social convention: if it is a pointer then it is your job to check for NULL. If it is a reference, then it is the job of the other guy to ensure it is not null. And the rules of the language mean that null references (as opposed to pointers) are rare.
"A reference shall be initialized to refer to a valid object or function. Note: in particular, a null reference cannot exist in a well-defined program, because the only way to create such a reference would be to bind it to the “object” obtained by dereferencing a null pointer, which causes undefined behavior"
Well then! That just goes to show how much safer C++ references are than I had previously supposed.