you're right, but people predict the future all the time, if there's a pre-established model for that prediction. I just threw a ball in the air and predicted how long it'd stay there </akshually>

so I think this comes down to how the predictions were arrived. One way to do this is to ask individuals who both have similarly high predictive scores and bet on the same types of events to explain some of their past predictions, and if their methods are similar then you've learned a new predictive tool.