[Tristan Lall]

I think it's worth discussing exactly what a successful replay challenge should be able to accomplish, in order to more clearly distinguish between good and bad policies.

It's probably inherently infeasible to unwind a match just because the participants' reactions to a bad call were different than they would have been had the correct call been made. That's worse than judging intent: it's almost complete subjectivity, and trying to speculate about what constitutes a correct outcome is an exercise in conjecture. Instead of expecting to unwind the match, teams should play on, with the understanding that the call on the field might be reversed on appeal. It's up to the teams to choose how they complete the match based on incomplete information, but the fact that in hindsight they should have chosen differently is of no consequence.

By contrast, a replay challenge might be warranted in situations where the nature of a discrete event is unclear, and where that event is supposed to have a defined result when determining the outcome of the match. For example, did the robot complete a game task for which points are supposed to be awarded? The resolution is to either award points or not, and that takes effect at the end of a match, no matter what else happened.

But what about games where score depends on intra-match conditions? Those fall somewhere in between, and probably need to be considered as part of the game design process. One possible resolution is to credit the points mistakenly not awarded, but not unwind the gameplay that resulted from those points not being scored at their proper time. (Is that equitable? I guess it depends on the game.) Another resolution might be to trigger a rematch for certain missed calls: perhaps they're so fundamental to the game that to miss one is to threaten the legitimacy of the event. (In fact, that's the sort of situation where a strong replay rule is beneficial: most of the audience already knows the equitable outcome, so why not give the referees the opportunity to get with the program?)

So ultimately, having a replay system doesn't need to mean that everyone will always get rematches and slow the event to a crawl. Instead, it should be tailored to the situations for which it is usually advantageous (and then applied consistently), and should be made unavailable when it would most often be detrimental.