As always, this sort of question is a test of competence by proxy and there are usually outliers, but statistically speaking, I think you'll find a very high correlation between inept programmers and people who don't know the difference.

I actually just sat down in a meeting with a dozen programmers, some of them with decades of experience, and half of them didn't know what functional programming was.

Your example shows that not every programmer has to know that.

I have a follow up question, "What are the advantages of a dynamically typed language over a statically typed one?"

This one kinda exposes the "Java-zellot" side of programming. If you love Scala and you're applying for Scala position, you don't often think like this. Being able to think critically about the things that are harder in Scala, that would be easier in a language without strict type checking, is a another good way to gauge if people can think critically.