To be honest all player characters, including MPCs, should be given the courtesy or RP before PVPing. While it makes sense for your paladin to jump straight into battle with a vampire harming an innocent, take note of the scene and show some consideration before you do so. You're not doing anyone any favors OOCly (neither the player of the monster nor of the victim) by diving into PVP with no RP during an otherwise roleplay driven scene.
I'm specifically looking at how players who use specific evil familiars, undead, and demons in regards to this rule, considering those creatures are indeed monsters.. even if they are in possession of a player. I definitely agree, should be for the benefit of roleplay, but at the same time, It's inconsiderate to use these creatures in a means that would normally provoke a response from another player, and then claimed to be protected by the rules because there isn't any RP. If an assassin imp started flying around the citidal invisible without saying a word, by that statement, the garda wouldn't be allowed to smack it?
- Monstrous characters are always allowed to engage victims at their own initiative, provided that it's done to serve the roleplay experience. Under the same terms, they are also free to be engaged if identified IC.
Players make their own choices, they can choose to use evil familiars and summons, just as they can choose where they use it. As Hatsune mentioned, I see these sort of things in the outskirts most times. Assassin Imps or Gremiskha running about, sometimes minding their own business, but they're still monsters. I have never had a single player ever preemptively hostile while possessing these creatures, and as mentioned, you as a player can't hostile them unless you know the owner on the player list.
The other issue is when players react to these monsters running around and presented with RP, and they just ignore and run away. If a caliban ran from the garda after being stopped, the garda probably shoots them, am I right? How is that going to be any different to confronting a creature of evil?