"If one should make a prediction so outlandish, they are an idiot even if their prediction proves true.”
This usually applies to people who make idiotic predictions (which do not always have to apply to sports)that most of the time would not come true, but when they would the predictor brags like he or she is some kind of genius. Idiot Theory disproves their genius.
B- Wow, she was right. They made it to the Final Four. She's a genius!
A- No, she's an idiot. Ever heard of the Idiot Theory of Sports?