How could it possibly not? Are you saying fair or foul shouldn't be reviewable? I think that's one of the easiest things to fix, especially on that particular call. Now, things change a bit if there was a guy on 1st who may have scored, but that's an easy ground rule double call to break up the no hitter once you see that ball hit the chalk. I think you can change fair calls to foul, but not the other way around(the exception being HR which have no on field action). Beltran's case might be pretty straight forward, but there's too many other things at play for me to feel comfortable with simulating action to get to a result. What do you do with runners on base? What if it's a pop up down the line that the LF or SS can immediately pick up and throw to a base? So the only way to handle it would be to give discretion to the umpire, the same umpire we're trying to take power away from because they just blew a call. It's like a runner being down in football. You can rule them down somewhere after the fact, but interpreting what would have happened when you've already called the play dead is too much hypothetical interpretation for me. What's the difference between overturning a foul ball on a HR and a ground rule double?