With regard to the possibility of error, we (humans) just need to learn to set our expectations accordingly. If a given source of information has a small possibility of error, a possibility of negative results due to negative information, and the potential to avert the negative results by acquiring the information, we need to tell ourselves that we will not be affected by whatever negative information we gain. We need to assume for emotional purposes that it is likely erroneous, until verified by other means.

With regard to privacy concerns, I agree, and I hope that existing or future regulations like HIPAA protect this information enough that the knowledge gained outweighs the risk of privacy lost.