As we know, Major League Baseball is the last of the major professional sports to fully use instant replay to review in-game rulings. Prior to this year, MLB only used replay if there was a dispute over whether there was a home run, now, most "non-judgement" calls are reviewable. Team managers get one challenge per game, with the right to earn another if successful on the first challenge. In the final three innings of the game umpires can decide to use replay at any time.
It seems to me that the frequency at which calls are overturned by replay is an indicator of the quality of officiating in the sport. Yesterday I watched the majority of two games, in one game two calls were overturned, both in plays at the plate. In another game one call was overturned. For all instances the call was obviously bad, and in my opinion highlight a problem in the positioning of umpires.
The calls at first base are particularly troubling. First base umpires usually move themselves towards second base in an attempt to see the ball coming into the first baseman at the same time that runner's foot touches the bases. I think a frequent problem occurs at first because runners are taught to touch the right corner of the base and continue running through, while the first basement's foot and legs are often at the second base side or in the middle of the base. In short, I think the umpire's view of the runner's foot is often blocked during the play and they have essentially been guessing that the ball beats the player's foot.
While most people have accepted the use of instant replay to help officiate sporting events, we still expect the officials to get the calls right in the first place. Ultimately, all sports that use replay need to use it as a tool to improve on-field officiating. If it turns out that the automated means does a better job, than officials on the field, it wouldn't be much more of a step to replace on-field officials with the automated solutions.