Hedging bets is almost always wrong. Say you bet a three-team parlay the third game starting after the first two are finished and you have won the first two. You now start thinking of having a sure profit by hedging the third. If you were going to hedge providing the first two hit why did you not just bet a two-team parlay? Go through the numbers and you will see that winning a two-team parlay pays better than a three teamer with a hedge for the third game.
There are times when hedging may be right. Say you were drunk and made a huge bet way over your usual bet size and now you are in a "hedge position". If the bet you made was of a size that if you lost would affect you a lot go ahead and hedge. Of course anyone who bets while drunk has no sense to start with so, maybe, this whole scenario is only academic.
Another case where hedging makes sense (I owe this example to King Yao), is if you stand to win a lot from some kind of free or almost free contest. Then locking up a sure profit which is much more that what your winning bets typically bring in is definitely right.