This posting is all over the place, but this comment in it is fascinating:

So why invent police? What are they for? In “The Institutional Revolution,” the economic historian Douglas W. Allen theorizes that their purpose was to preserve manufactured goods from theft. Before the nineteenth century, Allen writes, theft was easy to detect. If your transport was a horse, you could recognize it. (For that matter, it could recognize you.) Not only was your coat hand sewn, but a tailor looking at its fabric could probably tell who had woven it. If any of these items were stolen, they were easy to reclaim if they could be found. With the advent of the industrial revolution, handmade goods gave way to standardized commodities, which all look alike, and it ceased to be possible to know an object’s provenance just by looking at it. The phrase “possession is nine-tenths of the law” came into vogue, and it was made illegal to hold stolen goods. After all, once goods became untraceable, they were all too easy to fence.
The point about premodern goods being easy to trace is really neat, a great reminder that the past is a foreign country.  The original book sounds quite interesting as well:
The Institutional Revolution traces the dramatic shift from premodern institutions based on patronage, purchase, and personal ties toward modern institutions based on standardization, merit, and wage labor—a shift which was crucial to the explosive economic growth of the Industrial Revolution.
All this kind of throws into doubt all the thieves’ guilds of D&D and other fantasies.  It’s not that crime didn’t exist; it’s just unlikely that it was organized in a modern, quasi-corporate fashion. 
I should really start making a list of things that appear in fantasy novels that actually never existed in the past…