Is arbitrage betting haram?

Sometimes betting companies (who are of course bad) offer special promotions which gives you the chance to do *arbitrage* betting, meaning that it is possible to bet such that you win the same amount of money *regardless* of the outcome, if you bet the proper amount on different events. Is placing such a bet halal or haram? The money that you get does not depend on the outcome, moreover, you only take it from a betting company that ruins people. Also, if I *know* the outcome of an event for sure, is it allowed to bet on it at a betting company?