Basic suggestion, allow adding to be able to speak with more people while in prison but with more risk of the judge reading their messages. I would like the idea of judge's getting a page separate then normal messaging to read their prisoner's messages, so that they have to choose to go and look at them instead of automatically seeing them.
People you should be able to talk with IMO while in prison, all your liege's, ambassadors, and judge. So as a knight you would get to speak with your lord, duke, king, ambassadors, and your judge.
When you bribe the guards, there should still be a chance the guards send it to the judge to read anyways, although perhaps it decreases with your time in prison but increases with the amount of messages you send.
This way they have more people to talk with to work on getting himself or herself out of prison while also it being risky to send important messages even after bribing the guards.
