I like the idea of my noble enganging in combat... after all, if I'm not wrong, he not train just for duels and you won some swordfight in battle. I never trained with Erik at the academies and he always had high swordfight because of his infantry and a lot of battles.
In my last RP I used a subterfuge... I did the RP from the POV of a Bard paid by the char to increase his fame after wound a Perdanese noble. He said OOC he was wounded by a soldier and not a noble, maybe because the description goes by "wounded by Stormwalkwers" instead of "wounded ny Ehrendill"... so, the "Bard thing" saved me a silly OOC discussion.
Yea, I do find it limiting to go with the interpretation of "only those who pick this specific subclass can participate directly in combat", especially when that subclass comes with a "you can die" and a "you can never change your mind and opt out" clause.