Have lived this first hand in a large startup and thought... wait, we know our business and customer better than the folks you chat with once a quarter over fizzy water, why are we moving market position exactly?? (I was livid)
The later stage your startup becomes, the more conversations you end up having with your board members. It's no longer once a quarter, but often once a week or sometimes daily. While their word should not be treated as gospel, I've found that our VC board members have become extremely well versed in our business and industry.
If you ignore advice and fail (always the more likely outcome no matter what you do) then you failed because you refused to take advice. If you take the advice and fail, you can't be blamed. This is oddly powerful pyschology
If you're the boss, you'll be blamed either way. This should not be part of the decision process. The loneliness of being the boss...