It's worth taking into consideration, but wouldn't the normal situation be that maybe a lot of folk have only bought one item and opted to tell others about it ? I don't believe one can automatically assume the one review reviewer is necessarily a con. In fact were I do try to bolster an item I'd make darned sure I put a few dozen reviews "under my belt" to avoid suspicion. As is always the case, you make your mind up and go with the risks. Fair to say if you were in a shop you'd not get any reviews at all.