Unfortunately so many people lie about experience that you need to so some sort of whiteboard test just to see if the candidate really is fluent in the language they are claiming 5 years experience with. It can be a really simple test.
You must work in a super specialized industry, then
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.