Well, at some point day and night cycles as well as schedules will be implemented. So, I think some muggers might appear during night time when all the righteous citizens and lazy guards are asleep...
That's an excellent point. Something happening at night could actually work very well, and give the player something to look forward to (since I imagine the shops will shut down and the investigation opportunities grind to a halt) and/or fear. Players that want to avoid combat could always opt to sleep through the night, perhaps.
