based on what I know about their experience, the listed (and back door references)
If by "back door references", you mean that you check references that the applicant doesn't give, then you, sir, are a scumbag, and that'll be $25 for this consultation.
Why would googling a potential hire make him a scumbag? I've never hired anyone I didn't already know, but it seems to me that I wouldn't be willing to hire someone without actually doing a little research on them. Candidate-supplied eferences are supposed to be about character, but all they can really tell you is if the candidate was smart enough to only give references who would say good things about him, it would seem.
To have any component of the decision-making process that the candidate is not aware of is unethical, because it denies him the opportunity to improve his application in the future and successfully seek employment elsewhere.
The _best_ references I can get for a candidate are the dozen or so people that worked with him/her for the last five years. If I read you correctly, you are suggesting I roll the dice and not contact them.
More specifically, you are almost _never_ working for your current employer in Silicon Valley - your contributions and abilities are typically intended to impress your executive team, manager, and colleagues to position you better in the _next_ company - which is where you really see a strong stock and compensation package.
No Sr. candidates are hired without a strong combination of listed and back door references. And, the valley is strong enough that no candidate who has worked in the valley for 8-10 years won't have at least half a dozen colleagues in common with me.
If by "back door references", you mean that you check references that the applicant doesn't give, then you, sir, are a scumbag, and that'll be $25 for this consultation.