Myth: Physicians, exterminators, and entomologists can identify spiders.
Fact: Only arachnologists have the highly specialized skills needed to identify spiders, which take years of concentrated study to learn. To be sure, a few entomologists (insect specialists) and a very small number of physicians are also arachnologists, but the vast majority are not.
No medical school teaches even the basics of real spider identification; the most that medical students are likely to get is misinformation about identification by so-called "markings." Sad to say, numerous physicians have mis-diagnosed patients with mysterious sores, without even seeing a spider, as having been bitten by spider species that did not even exist in their locations.
Most pest control operators have very inadequate training even in the identification of common pest insects; few are trained entomologists, and I know of only one in the United States who is an arachnologist. Misidentifications by non-arachnologists are the source of a very large number of false spider reports and "scares" in the news media.