I have a CS degree. I learned about the CAP theorem, and I work with the nature of it daily. But my mind have ventured beyond the CAP theorem, it's implications are now mere facts of distributed systems, and the name "CAP theorem" had simply sliped out of my mind. If you want to quiz knowledge, rather than google-fu and name dropping, ask if you can make a distributed system with consistency and availability.

I think this indeed would be a better approach.

Instead of asking about Bubble sort, ask what is generally the complexity of a naive sorting algorithm and how good it can get for a general case.

I have investigated immutable hash tables but I do not know much about concurrent hash tables. This is my blind spot, so I do not know what the relevant question about the Hopscotch hashing would be.

Instead of asking what is CAP theorem, ask if you can make a distributed system with consistency and availability at the same time.

I think that this was the intention behind these questions after all and is the reason why I am trying to argue in support of them.

There's a middleground between those extremes. There's lots of knowledge that isn't relevant most of the time, but when it is relevant its worth its weight in gold. (And often these things aren't so obvious that people will google search them.)

When I'm trying to evaluate a candidate, I want people who proactively search out knowledge in that middle zone. People who understand complexity theory, and CPU caching behaviour, and the C10k/C10M problem just because they know they might need it some day. Because they want to work on problems where this stuff is relevant.

This sort of knowledge is the difference between hearing "our website is slow - I think its the database?" and "our website is slow - I took a look and our database server has run out of open file handles. But I'm still confused - that shouldn't explain the latency we're seeing."

The CAP theorem is a great example of this sort of middleground might-be-useful knowledge. Understanding how your database will behave in the face of network partitions is exactly the sort of thing that separates good engineers from great ones.