When you notice players disagreeing on whether normally accepted methods (dice, coin etc.) work, it is often a sign that the players dislike each other on some level. Fixing the specific situation quickly will normally mitigate this. As something bigger may be afoot, careful considerations of everyone's feelings are important. You may want to keep an eye on the table (logistics permitting) so that you are in a better position to address any future conflicts before they become a serious problem.