Infiltrator like any character that gets caught can be executed by a judje,so he should at least be allowed to kill his target.It makes no sence to take such risks just for the sake of wounding another character.
As for adventurers they should be very hard to capture and must first be discovered.Like a search for adventurer comand or something.You lose 8 hours and may not even find the adventurer.
Remember, infiltrators have many, many targets, while to retaliate there is only one infiltrator. Thus it is sensible that the risk for the ability to attack many others is higher than the damage dealt to each
individual noble. As Rob mentioned above, infiltrators don't even get the option to be executed unless they get caught twice by the same realm.
