That's a fair concern. We really try and avoid advancing anyone when we suspect might be rejected in the middle or end of our process. It has only happened once since I've been here. Again though, I have to lean back on that everyone should be aware that job hunting isn't an ideal process. Occasionally someone can really ace one part of an interview and really not be a fit in a different part. It's unfortunate when it happens, and that's when I lean on my principles of offering constructive feedback.