I remember thinking what you're writing about there, that there's a lot of people to be filtered out, and that good candidates wouldn't be offended.
So we had this simple two-part quiz question for people, starting with "what is the expectation of a dice roll?". Amazingly a lot of people can't figure this out.
But also a lot of people know the answer immediately and will wonder WTF you are asking such a simple question for. I remember this one lady who interviewed with my firm, the look on her face when she realized we weren't asking anything complicated. You could just tell she thought we were a bunch of amateurs, and she'd better be on her way to see some other proper hedge funds.
But I think the point in this thread is the Google question about Linux inodes was actually part of a pre-screen interview done by an outside agency.