Should we trust politicians or famous people? Not because of their position, not at all no. Should we trust people that have studied years and years on a certain subject, who can be considered experts, and that for the great majority all agree on one issue? Yes, unless we have strong reasons not to. Many people doubt the opinion of experts without any good reason to do so. If that attitude (or lifestyle even) gets out of hand (and I am exaggerating slightly), schools and universities will be useless, because anytime a teacher tries to teach students any 'facts', students will not believe him because there are no facts.

You will find a nice example of what I mean in this scene of Thank You For Smoking (awesome movie), "Your mommy says you can't smoke? So is your mommy a doctor?"