As you probably know, Skyrim has radiant Bounty Quests to obtain from the Steward or Innkeeper of a Hold. My idea is that if the bounty is a humanoid NPC (Bandits, etc.) you get the choice to spare them and arrest them, and then escort them to the Hold's Prison. With this mechanism, there could be a % chance that the prisoner could break free of the bindings and either A) Attack or B) Run for it. Also, maybe you could bind them and leave them in their cave or hideout, and then when you go to tell the Steward this he rewards you and sends a couple of guards to retrieve the prisoner. Maybe you could later see the prisoner in one of the originally vacant jail cells of a hold.