I've joked that when a philosopher says there's a philosophical consensus, what he really means is "I talked to a few of my friends about this and they agreed with me.

I came across a term to describe this phenomenon in linguistics regarding grammaticality judgements: Hey Sallys. The idea being, you form some theory about what's grammatical based on what sounds good to you, you think that you ought to check to make sure you're not just being idiosyncratic, and so you wander out into the grad room/house/water cooler/etc and say "Hey X, how does this sound to you?"

Having said that, there's a paper somewhere showing that individual linguists' grammaticality judgements are just as good as taking a large survey in the vast majority of cases.