The initial decision that it was a forward pass was a mistake, but it wasn't a mistake to blow the whistle after making that decision. The air-headed announcers kept saying that the refs need to let a play like that go and then sort it out by reviewing replays. Not true. You have to make a decision on the spot. If you favor one team over the other in making the initial call, you are stacking the odds in that team's favor for the following reason: the call cannot be overturned unless there is indisputable evidence. Since the replays are not always conclusive, it is an advantage to have the initial call go your way.