The original meaning of the verb 'to hedge' was just that...literally to plant a hedge around a place to provide safety and security. That same meaning applies to bets. If you gamble that 'Outcome A' will happen, it's a good idea - if you can - to bet that it'll be 'Outcome B' instead! Thus, you can't lose...your money is secure and protected whatever happens. Bookies and stock-market traders do it all the time.