Obviously nothing in life is 100% but when Steph Curry and Kyle Korver are on balance, do everything perfectly in their shooting, they feel like it's good - I would bet that it's going in MOST of the time. It's why Curry was able to shoot a 3 and not even look to see if it went in. Sometimes when guys are open, they don't handle the ball correctly, their lift isn't perfect, they short arm it, etc. But sometimes they do get everything perfect and it's most likely going in.
I don't mind the green releases cause of that. If they lowered it to 70-80% vs. 100% - I'd be fine with that. I think the 100% is fine as long as they make it difficult to do - and impossible to do under certain scenarios. Like on the move, while contested, with bad shooters, etc.