Watching Olympic men's volleyball (USA v Canada) I noticed you get two requests for video play review but the request doesn't count if the decision was reversed in your favor.

In other words, you aren't penalized for requesting a review of a call that was clearly wrong. It's the officiators' way of saying, "OUR BAD."

I like that a lot because it holds the judges/refs/umps accountable.

But I'm not sure it would work in the NFL or other professional sports where participants frequently act in ways that are unsporstmanlike if there's a slim chance of benefit (like fouling your opponent repeatedly in the last two minutes of a basketball game).

Limiting play review to 2x means coaches act selectively on delaying the game. That's wise. So, I'm not sure unlimited (reversed) calls is the way to go.