The question of relevance reminds me of an anecdote. (Before that though; I tend to agree with your points.)
A distant acquaintance interviewed for a secretary position. It didn't go well, because she was asked a general knowledge question (something along the lines of: "name some of the planets in the solar system"). She was furious with how irrelevant and unfair this was. It makes me wonder though, would I have hired her? I probably wouldn't have asked that question, but still. When someone is missing some really basic knowledge - even if it's irrelevant - it's not a good sign, per se.
One of the things I like to do is ask a factual question about a technology listed on the candidate's resume that isn't required to know in order to hack something together, but is something that "you should know" if you've been working in a particular technology for a few years.
These are part of the warm-up, I'll ask one or two right at the beginning of the interview and then move to the real questions.
Examples are: "How does the autorelease pool work?" (Objective C before everyone switched to ARC.) or "How do you ensure that an object is garbage collected," (C# and Java.)
These are more about judging a candidate's real knowledge versus stated knowledge. Someone who's spent 8 years in Objective C better know how to use the autorelease pool; and someone with at least a year of experience in a garbage collected language better know how to ensure that an object is collected.
As someone who has worked in C# for about 8 years: you can't.
You can call `GC.Collect()` and hope. But far as I know the GC will do a best effort and gives no guarantees.
Of course that's besides that fact that I would need strong arguments to accept a `GC.Collect()` anywhere in the code. But to call it just to ensure an object is collected? Oh boy..
Depending on the case you could add some code to the `Dispose(bool)` method to know when your object is collected, but also in that case you risk flipping a Bozo bit.
Well, aside from categorising such basic knowledge as "trivia", it's definitely not about taking one random, useless fact, and failing the interviewee on it. Rather, it's an example of a lowest common denominator question that everyone who has primary school education should laugh at, and move along. Hitting a hole at this level does imply some major issues with the person's general knowledge. It's fair to wonder what else will be missing in that person's repertoire, and how they will cope in random situations.
Similarly, if a programmer fails the question "in the alphabet, which letter comes after A", I'd be worried, and rightfully so. I'd give them a chance to recover from that, just to make sure it wasn't a once-off, but it's not excusable.
A distant acquaintance interviewed for a secretary position. It didn't go well, because she was asked a general knowledge question (something along the lines of: "name some of the planets in the solar system"). She was furious with how irrelevant and unfair this was. It makes me wonder though, would I have hired her? I probably wouldn't have asked that question, but still. When someone is missing some really basic knowledge - even if it's irrelevant - it's not a good sign, per se.