Honestly, I keep hearing stories of companies doing interviews that are pretty much brain teasers and exercises in CS101 recall all the way through.
Say you're hiring a web developer. It's good to ask one question out of left field... "How many times do the hour, minute, and second hands of a clock perfectly align in 12 hours?"... to evaluate thought processes and see if the applicant dives in. But the reality is 90% of web development work at 90% of companies is pretty basic.
To the framework jockey who can turn out excellent, well tested code, even CS101 questions about recursion are pointless. Big-O notation is useful, but not often used. Blah blah blah.
When I interview, I'm looking for smart, socially well-adjusted people who have a track record of getting things done and not pissing their coworkers off. Questions are directly related to the position I'm hiring for, with one "fun" one - and I'm clear that the brain teaser isn't a right/wrong pass/fail scenario. If the people they'll be working with think they're a fit, they're hired.
And if they turn out to be all talk, we'd can them after the first month. Hasn't happened yet.
Now, for a senior role, I'd be choosier, sure. But to discard someone for not knowing an arbitrary piece of software or bit of theory? Baby/bathwater.