I'm liking this thought. But I think that instead of NPC guards, members of the kingdom's guard need to be given a capture command, which imobilizes the target, forces the target to follow the capturer, and requires the capturer to go to the jail to release his captive.
If the capturer takes too long to get to the jail, the captive has an increased chance of going free. The command will have a higher chance of success at higher ranks. Failure to successfully capture will either start a fight or cause the intended captive to run off in a random direction.
For example: Savvy, a guard in Mesilena, will have a very low chance of capturing anyone unless they are far below her level (at least 20 levels). Kinnaz, as a Sheriff in Murkwood would have a decent chance of pulling off a capture without starting a fight as long as he is within 10-20 levels of his intended captive. Ariadne, as Chief Justice of Calararian, would have a very good chance of capturing even those enemies who are 40 levels above her.
I just think that if we are going to use jail for IC reasons, lets use the IC characters who would be responsible to carry out the sentence.
Thaxn