the best way to really know would be to track the betting action. in vegas they can take a proposition "off" or closed. i'm sure the sports books in vegas took a lot of action on that match and it would be nice to know if any "smart money' or wise guy bets were made. that is large bets made on billie jean king to win. if riggs was into bookies for a large amount of money the fix has to be considered. who did he bet with and who his manager was, things like that have to be fleshed out. of course it's easier said than done.