I'm not sure I get all of that out the article, but there were a couple of red flags for me as well. Assuming that Credit Suisse surprised him with the coding

I'm not sure I get all of that out the article, but there were a couple of red flags for me as well. Assuming that Credit Suisse surprised him with the coding section of the interview, I can't necessarily fault him for walking out, because at that time, he realized that he didn't want to work for that company. The response to the riddle is arrogant. So you don't like riddles, that's fine. Extend the same courtesy to the interviewer that you would want to see as an interviewee; if you don't want to work there, politely thank them and leave. Asking to see open-source contributions is fine, but I don't agree with the idea of giving somebody homework. They could easily ship that work out to a friend or hire a cheap contractor. More importantly, it's the company investing almost nothing in the interview process, and yet asking the candidate for a substantial amount of return. During my interviews, I have candidates pair up with team members and work on code. This is subtly different from homework, in that my company invests as much in the interview process as the candidate, which pays off as members of you team get a test-drive of what the candidate will be like on his first day.