In my two decades of experience, I've never seen another software engineer implement a linked list or even use a linked list. There are better, and more interesting, questions to be asking.
I personally wouldn't expect someone to implement one (end cases easy to mess up if they are stressed), but writing a function to reverse one (foreach, pop front, push front) is enough to catch the liars. You can argue about how often a std::list vs std::vector is a performance win, but I'd run a mile from any developer who wasn't highly familiar with the basic data structures provided by any language they are claiming to be fluent in.
The only real requirements to "never use a linked list" are a) use a language where some kind of contiguous-storage-based sequence (array, vector, whatever you want to call it; Python calls it a list, even) is built in (or in the standard library); plus b) not ever need to remove O(1) values from the middle of a sequence in O(1) time while preserving order.
But arguably, a candidate who hasn't ever had to contemplate the concept of "linked list" but can derive the necessary ideas on the spot given the basic design, has some useful talents.
