An excellent point and suggestion.

Any test in which there are confounding variables should be suspect, and every attempt should be made to eliminate them. Looking at 'winners' isn't useful unless we know the way in which they won indicates rationality. Lottery winners got lucky. Playing the lottery has a negative expected return. Including lottery winners in the group you scrutinize means you're including stupid people who were the beneficiaries of a single turn of good fortune.

The questions we should be asking ourselves are: What criteria distinguish rationality from non-rationality? What criteria distinguish between degrees of rationality?