I do see what IB is getting at, he's just making his point badly. I may be wrong, but I think he's trying to say, when you buy a used car, because the salesman has been around the cars for ages, dont take his word that the car he's trying to sell you is a good deal because he says it is. He's trying to make the arguement for suspending blind trust, which would be a valid point to make. The examples are poor examples that''s all.