An argument that is often used by believers in unusual theories is that since some more conventional explanations require that a person has made a mistake, and since that person is a highly trained expert, then that means it’s highly unlikely they would make a mistake, and hence the conventional explanation is highly improbable, and so this puts their unusual theory at the top of the list.
The classic example here is with UFOs. The “expert” witness is often a pilot ... Read even more