Makes no sense. Let's take Fabernum as an example. You go around breaking the law and lose reputation with the owner of the city (Tindremic Empire) to the point they hate you. You basically get black listed and the guards attack the enemies of the owner.
When a player guild takes over the city and becomes the owner, you go around and break whatever laws they have, you become "detested" by them. Guards should do the same thing: attack the enemies of the owner. Since guilds can have any type of law (e.g. don't clutter the bank with horses), there is not an in-game reputation/law system for each individual guild so it just boils down to how much that guild dislikes you. The black list is a method for guilds to flag you as "detested".
You go mess with the guild that owns a city, expect consequences.
Furthermore, members of the owner guild should be able to attack anyone inside their city, black listed or not, without going grey. They are the owner and they are the employer of the guards. Guards need to look the other way. If they don't like what their employer does, they can quit their job.
There are ways to not get black listed and killed in a town you want to spend time in:
- Don't mess with the guild that owns it.
- If the guild is using their ownership to kill randoms and grief, you can get together and siege them, taking away their ownership.
If you want SV to hold your hand while you already have the means to control the outcome then perhaps this isn't the game for you.