First of all I do not see why this class is limited to nobles.It is not really something that requires noble blood.So I think adventurers should be allowed to switch to infiltrators.
Secondly infiltrators should be able to actually kill their target and guards should be able to kill infiltrators.To make things fair the chances of this would be low,kind of like the chances of getting killed by monsters as an adventurer.
Adventurers aren't tied by turn changes. You could stab someone and then be 3 regions away in just a few seconds. It's just too powerful of an advantage.
Adventurers killing people they stab has been requested a few times as I remember it. Every time it has been turned down because character death should mostly be the choice of the player playing that character.
