Implement a challenge system, MLB

[mbyron]

What about catch/no catch? That's one where replay would be a mess.

Reviewing the third out: no significant disadvantage is likely here. False positive (3rd out incorrectly awarded to the defense): the offense gets to keep playing, so they won't mind if play has stopped (except maybe on scoring plays if the runner has to go back). False negative (3rd out incorrectly withheld from the defense): the defense won't mind if play continues, because the inning will end and runs possibly negated.