There's basically no reason to disagree with this concept. The people who have disagreed have not put forth one single reasonable explanation why dueling shouldn't be considered a crime by the guards. They're misunderstanding the concept; thinking people are against dueling or against dueling in cities. That isn't the case. What we're saying is that guards that spot people dueling should react as they do to other crimes.
If you want to duel, and not get harassed by the man, take it behind the stable. It's a win-win solution.