1) You only leave theft clues when you actually take something from a container. Merely looking leaves a trespassing clue.
2) Crime scents can be compared. Hold a scent, right click on another scent, and the game will tell you if they were left by the same perpetrator.
3) Stolen items can be tracked. Quite simply. The tracker points to the person/basket/container/house/mine/whatever that holds the item.
4) Stuff(tm) can't be placed on the black nil tiles indoors.
5) We're working on something nice. You'll be able to figure out what if you take a good look around.
That's about it.