The issue I hear with dueling is though with the roleplaying is someone has a great reason for a duel but the other person is worried they will die and get no benefit so they dont accept. No one treats the person who didnt accept as a coward and everything keeps going the way it was before. This is what I have heard from many. So to solve the issue if you give reasons why someone should actually accept a duel then they will happen instead of nobles getting to insult and do other things worthy of a duel but the player is too afraid of losing their character. I am not trying to make a new way to "get more calvary" but to make duels happen more often when they should instead of cowards who get no punishment for the way they act.
