Debunking is a colloquial term to denote the exposing of false or exaggerated claims. In UFOlogy, it refers to the discrediting of UFO reports and sometimes the witnesses themselves. Many UFOlogists believe that the United States Air Force (USAF) carried out an intentionally indiscriminate debunking program during the course of its official investigations (See Project Blue Book and Project Grudge). Many witnesses were ridiculed and their reports given conventional explanations that, in many cases, were unsubstantiated. This led to the belief that the Air Force knew something disconcerting about the UFO phenomenon and was involved in a cover-up. Some UFOlogists have speculated that the Air Force believed, and still believes, the public needed to be protected from the truth. Others have conjectured that the Air Force attempted to debunk UFO stories rather than admit their own ignorance regarding the truth nature of the phenomenon. Whatever the reason for debunking UFO reports, the subsequent embarrassment experienced by some witnesses discouraged many others from reporting their sightings.