The best players will not concede unless they know what they are condeding to without any uncertainty.
Not 100% true. Sometimes you will want to concede so you have time to play games 2 and 3 even without seeing every card in your opponent's deck. If you are at a point where you have basically no chance to win and your opponent is gonna take 15minutes to eventually kill you, theres nothing wrong with conceding there without waiting to see their whole deck. I agree that its very useful to actually see the kill card, but if it will take 10-15minutes before you even get to that point in what has already been a long game, that extra time will be much more valuable than knowing one or two extra cards.
Edit: To the post above me: It's not cheating. It's not against the rules. Hidden information is just that, hidden. If someone asks if I have FoW in hand, I can lie if I feel like it because I have no obligation to be honest about hidden (or derived) information. Just like if I cast tinker and say "Can you even beat Plats?", I have no obligation to tell the truth. It's HIDDEN. Now, they can make me show it, and then I have my bluff called, but if they don't, it's on them and nothing illegal has occurred.
