There’s often a big difference between perceived risks and actual risks. Understanding the difference may be important to people in the information security industry because people probably buy security products to mitigate perceived risks instead of actual risks. Even more tricky to deal with are "virtual risks," in which there’s no easy way to determine what the real risk is or when experts can’t agree on the nature of the risk.
One area in which it’s not clear what type of risk really exists is in deciding whether or not cell phones pose a health threat. The Interphone study, a six-year study that cost $30 million and involved scientists from 13 different countries, tried to assess whether or not such a threat exists and come up with very mixed conclusions. Some researchers are claiming that the study showed that cell phone use seems to prevent certain types of cancer. Others are claiming that the study showed there’s no connection between cell phone use and cancer. There’s apparently no consensus on what the data collected by the study really means. In the absence of a meaningful scientific consensus, people will probably decide what to do based on what they think the risk is, so the issue of cell phone safety may soon enter into the realm of virtual risk if it isn’t there already.
An even stranger situation seems to have happened in Sweden, where some people apparently have "electrosensitivity," or the unfortunate situation that electric fields cause them pain. The Swedish government has recognized this as a legitimate disability and will pay to have the houses of sufferers shielded. The catch is that electrosensitivity is totally psychosomatic. The discomfort felt by sufferers of electrosensitivity is real, but it’s also not actually connected to the presence of an electric field! So this may actually qualify of a real risk, although it’s certainly different than the risks that we usually worry about.