I don't have such a great concern here, Simon, in that the running it through twice principle is (a) usually publicly known and (b) an option available to all at the table. If a player refuses to run it through twice with you, but accepts it with another player, you would have good grounds for calling the floor and claiming evidence of collusion. However, it's my understanding that the double run through is eiter always accepted or always declined (a bit like splitting the blinds).

PJ