In my recent game I nervously decided to start rebuilding in The Hub, in spite of a low presence of guards and high presence of bandits. It's a fairly lawless place, by all appearances.
And yet it is the sort of town, like all other towns in Kenshi, where you feel entirely 100% safe leaving your door unlocked, even wide open, for weeks while you are away.
The various shops and bars in every town are always watched carefully by heavily armed guards -- even at night there is almost always security present in every building. But players have no reason whatsoever to need similar security of their own. Apparently that security exists solely to protect against the player's thieving ways!
So! I propose similar events like we experience with our outposts, only tailored toward townie life!
- Cat-burglars: They come at night and test your locks. If they open the door and remain unchallenged, they enter and loot whatever they can carry back out. Of course, they come prepared with backpacks to facilitate carrying out loot.
- Squatters: They come when your building has been observed as abandoned for a while, and squatters may belong to various factions. Some squatters may be capable of violence, and some may be civilians. Some may fight to stay, while others may scatter the second they're spotted. In most cases they will also take for themselves any items that interest them.
- Protection: Bandits or some other gangsters show up at the building demanding tribute, similar to the Dust Bandit raids on outposts. If the player gives in, they return for future payments. If the player refuses, they return one night to dole out punishment and make an example to others.
- Contraband Raid: The dominant local faction shows up for a surprise inspection of the premises to check for illegal production machines (such as for Hashish) and if the door isn't opened for them they'll happily bust it down. If they find any contraband, all characters present will be beaten and arrested. (I wonder if it would be too cruel to have a building repossessed, but I imagine this is what the Holy Nation would do, and perhaps the Empire.)
Just some ideas -- I'm sure there are other events which could be applicable.