I think Google prefers false negatives over false positives. I know a few extremely smart people who didn't "pass" their Google interviews. Most likely because they didn't have that "totally positive effortlessly nice and socially easy" vibe.
That's probably the right attitude to take in hiring. Bad code is difficult and expensive to discover and fix and a bad hire is difficult and expensive to let go.
With proper code review, I don't think bad code is difficult to discover. I also don't think dismissal is very expensive for large corps. For smaller companies or start-ups, the game is entirely different.
