The more we want it to be true, the more careful we have to be. No witness's say-so is good enough. People make mistakes. People play practical jokes. People stretch the truth for money, attention or fame.
People occasionally misunderstand what they're seeing.
People sometimes even see things that aren't there. Just conceivably, a few might be small comets dissipating in the upper air. There was the suspicion that the field attracted rogues and charlatans. Farmers or passersby would discover pictograms impressed upon fields of wheat, oats, barley or rapeseed. Beginning with simple circles, first reported in southern England in the middle 1970s, the phenomenon progressed year by year.