Should site reviewers be required or expected to recuse themselves from doing a review of a site if they are asked to review a site for which they have a personal bias against due to friendships or competitive relationships with other people or websites?

I would think in the interest of objective and honest / unbiased porn reviews they should because otherwise it taints not only the review, making it a personal weapon, but also the reviewers reputation if their relationships causing such bias come to light.

Just a hypothetical question. Your feelings?