I don't really get why "reversing a binary tree" seem to be used as an example of what's wrong with hiring. I will say, though, that if someone said "how do you reverse a binary tree?" I would have asked the follow up question: "what do you mean by that?". If asking that would be used against me, sure, that's bad hiring.
But if the answer is: "swap all the left and right nodes in a binary tree", then... isn't that pretty basic programming?
I find high end jobs tend to ask some form of problem that can be tackled using dynamic programming techniques. Maybe couple of easier ones in the first interview.
I agree with most people. I never use these skills in the job. I think they're a intelligence test in disguise.
I mostly agree with your impression, though even after adjusting for intelligence I bet there's a positive correlation between knowing how B-trees work and, say, having a good intuition for how to index a database.
But the purpose of the question of course is to be an easy question showing basic competency in recursion and pointer usage.