Unfortunately the CS trivia is necessary. In a previous job I interviewed people who snuck past the phone screen and would have wasted a ton of interviewer time if some CS-101 questions hadn't exposed near total ignorance of the highlights on their resume. My favorite was the guy who applied for a job as an air traffic routing researcher and after 20 minutes of computational geometry questions said, "Wow, tough, do you do a lot of math here?" Yeah dude. This is NASA. We do a lot of math here.