In the usa, people tend to look at the world in very simple terms. They will believe that one should follow the recommendations of the "professionals" in every case. In fact, that's often not a good course. One should think critically and independently about the world. This is true also when it comes to matters of personal health.
As in many areas, Canadians seem to be much more wise about these things. Here's a Canadian Broadcasting Corporation broadcast which looks at the dangers of prescreening people - specifically screening men for prostate cancer.