Economics: Justice

There are many spells that you might imagine using in a court of law: Zone of Truth (cleric 2),  Discern Lies (cleric 4), Divination (cleric 4), Charm Person (wizard 1), Detect Thoughts (wizard 2), and Lesser Geas (wizard 4).

So you could imagine that spell casters could be pretty good judges. But you could even just use a Hallow spell with Zone of Truth. This creates a fixed Zone of Truth that lasts a year for 3,000 gold. This makes a pretty good court room, but it seems like having a low or mid level cleric or wizard on retainer as an interrogator makes more sense.