Communally Revealing Cards Without Ability to Reneg Profitably
Firstly a thought about gameflow, reneging, and card reveal. If it can be that a card to be revealed is “chosen” or at least for example the backside of the card is known to all players, there should then be the possibility of forcing each player to participate in revealing the card or to forfeit there own equity in the hand.
This suggests there can be no reneging on a street card (or cards) in order to only have the last move valid and not the street card(s) that were revealed.
This means no significant gain can be made from reneging since we can simply force the equity to be paid out for the hand to the live players. It also means that it cannot be feasible or profitable to reneg in this fashion since it would cause villain to lose their equity in the pot that they either have (ie > 0%) or don’t have (ie 0%).
This seems to cut the problem and solution down to a player that refuses to cooperative loses their equity.
Using the (Poker) Block-chain as a Credible Threat vs Renegers
In regards to lightning channels, LC’s allow off chain transactions that truly need never hit the block chain except for those instances when one of the involved parties doesn’t cooperate with the protocol (whether they mean to not cooperate or not). Knowing that the block chain proof is there is plenty enough for rationally interested parties, since there can be no monetary gain from not cooperating and yet there is some loss to the reputation of the non cooperating entity.
There could be an analogy in regards to a poker hand history. Since a poker hand is played within a finite amount of time (players turn + players time bank), there can then be different types of timestamped (and possibly locktime) solutions that allow a suspicious player to write a suspicion to the block chain. If all players are required to monitor the block chain and especially for their own table/play, it is then up to the suspect to answer to the suspicion with the appropriate hand history decision they are suspected of not providing. Then the accuser can choose to end the inquiry and go back to the game at hand, or can themselves respond to the original suspects accusation if there is a new one.
In other words its like being able to flip the game to public record in order to enforce play, and although such play would definitely ruin the game flow, the conjecture is it is quite enough to dissuade cheaters from believing that this kind of cheating COULD be profitable. It is a credible threat.