Well, in american football, yes. If the coach thinks the ref made a bad cal, he can challenge it. It then goes to a video review and if the ref decides that the coach is right, they change the ruling. It has made the game a lot better in my opinion. Ref's are people too. They can't see everything, so they miss calls or make bad calls. It's nice to have the ability to say "look at the tape and tell me what you see".

For example, I was watching Ski aerials (I think thats what they are called) and four guys in a row did the exact same trick. They looked virtually identical and the judges are not allowed to look at slo-mo replays. All the guys got quite different scores. With the speed that the skiers are moving at, there is no way that the judges have time to see each trick (which last about three seconds) properly. I think letting the judges view replays would help matters.

When I watch this "judging sports" the commentators usually seem to agree with the judges even though I rarely see the differences between what the contestants do. That tells me that the judges are pretty good at seeing what is good and bad with a contestants performance.