"Concede to a Counter ... OK, Not Conceding"
The idea of offered conditional concessions as a proposed “contract” seems much more correct to me than hairing this as a possible “in-game shortcut”. Thats because the outcome of the loop would directly affect the match and end the game possibly. I consider it a match action, not a game action. You see, concessions are mentioned in the comprehensive rules not because Wizards graciously allowed players to leave the game at any time, but because there is no legal possibility to force them keep playing in the first place. It was just deemed a good idea to mention it in the rules, because the possibility of lock-down decks existed since the printing of Alpha.
As is the case, conditional concessions are a grey area, because of the mentioned ambiguities of exact or more or less fitting cards in the opponents hands. (However, not in the first example, there the criterium was met fully). I'd prefer this fog to be lifted, one way or the other.
Given the possibility that there are countries in which the law holds players to verbal contracts, I'd want to prevent players pondering legal ramifications. I'd rather have a section of the tournament rules clarify that condtiional concessions only become binding if the exact card asked for is in the opponents hand. I found generalisations like “Show me a counter/removal/sweeper and I'll concede” always to be a little problematic, but luckily I never encountered a situation in which the revealed card was not able to seal the deal. Meaning, I never encountered a player who wanted to trick the deal with a card that couldn't win it. Likewisely, I never want to encounter a player who gets what he asked for, and then plays on. That behaviour is so brash, it could put even spectators or the judge on tilt. I deem it wrong of us as judges if we let the community care about such “undesired” behaviour, because we are part of the community as well, regarded by some as representatives of it, even. It is our duty to have an opinion about the issue, and it better be well thought-of opinion, and preferably in hard rules text - tournament rules text, to be precise.
My last point I want to adress is my side step from my last comment: Players have indeed been penalized if they didn't play the game in an attempt to advance toward a win. From the comprehensive rule perspective, we can't make them reveal hidden information they want to keep hidden, but from a tournament rules perspective they act wrongfully nonetheless. It was my bad that I mentioned the wrong rule - it seems I thought of USC-stalling the game, not slow play. (An excursion from Example B: “A player is ahead in games and slows down the pace of play so that the opponent has little time to catch up” - here: A player knows of his bleak chances against sideboard cards he knows are there in game 2 and 3, and prolongs game one willfully in an attempt to preserve his victory in game 2 by outrunning the clock, causing a draw and thus taking the match). I just wanted to stir some thoughts with the example, I don't intent to let myself be called to a match to observe wether a player has a certain card in hand so that the opponent can concede “safely” to him in the near future.
Once we clear the issue for good, it might be necessary to change the rules even if we don't want to change the current legal situation: We then should just mention in the rules that offered concessions that include the condition of revealled, certain or specific, cards from the hand aren't binding in any case. That way, players have at least a chance to not fall into this trap if they were totally new to competitive play (and only read the rules beforhand). Having players understand “derived” rules knowledge seems too much to ask of them.
And that would be the least I could agree upon.