Executions work just fine the way it is right now. Infiltrators already have a good chance to auto-escape when the Judge tries to execute them. (Remember that you only see the results of executions that were successful.) Deportation is a slap on the wrist. Ban is like hitting your wrist with a feather.
None of the other classes are effective until they "train up". Warriors will not win any tournaments with low swordsmanship, or be able to fight off an enemy Infiltrator. Courtiers can't raise region stats very much. Diplomats and Priests are pretty much worthless the first few weeks on the job. Why should Infiltrators get special treatment?
The only problem I can see is the click-wars between Infiltrators, knights tasked with hunting them, and Judges. Making the "patrol the streets" police option effective even after the Infiltrator has acted would help on the part of those acting against Infiltrators. I'm afraid the Infiltrator class itself is always going to attrack turn-junkies. If you stab someone early in the turn, you disable him for an entire turn. If you stab someone late in the turn, he might be disabled for only an hour.
