Not to say asking puzzle coding questions is an ideal approach, but I think the motivation is somewhat opposite: If you base your hiring decision on how awesome the applicant tells you they are, a certain number of the people you say "hire" for are going to be bullshit artists who can't code. When the interview is over, the interviewer is judged either explicitly or implicitly on how well they conducted the interview, and there's probably nothing worse they could do than say "hire" to someone and have the next interviewer find out they're lacking basic coding skills. So they have to ask some kind of coding question, and it has to be something with some meat to it, but you probably can't make it too OS or framework specific, so you're left asking about overlapping rectangles.

Compliant, with lots of “free” time...