Originally Posted by
LisseyCrowe
Not to be a party pooper but I think you guys are thinking too hard about the rubber bullets, or at least backwards. That is to say, I was under the impression that the rubber bullets were exclusively for duels, not the other way around, hence the red-headed guy going "Using rubber bullets, of course", as if to bring attention to the fact that that's not the usual ammunition in those guns.
Granted it's still dumb, like someone got worried duels to the death would be too savage or uncivilized (which, to be fair, I agree with) but that's where you probably add a "If the duel ends in death, there are no winners and the killer gets jailed" rule instead to enforce some civility.