Alright, rather than just saying yes here are some actual points since I got nothing better to do right now.
I have been on all sides of the rescue mission rp/pvp. I can tell you right now that every single "negotiation" I had was either "You will all come here and surrender or else..." or it was "We want your leader in exchange for the hostage". Yeah, neither of those are ever going to happen but why is that the case? Well if we want to understand why that's the case we have to think about what should we ask for during negotiations. I have barely ever heard of negotiations going in the favor of the, in this case, a hostile party, so what is there to gain for them? Simple answer: Nothing.
Any scenario in which they give up the hostage they lose all the leverage they had and they'll get lit up like a Christmas tree. Of course, I can "negotiate" for the attackers to spare our lives if I release the hostage but that isn't rule binding. Just because they tell me icly I'll be fine doesn't mean they are renouncing their KOS rights. In conclusion, if I have a hostage in most cases I am not interested in negotiations since it is a game I will lose.
I haven't been a hostage in a long time but what else would I expect but getting killed if my captors take shots? Revenge is a very human thing and even if they don't really gain anything from killing me, would it be a surprise? No, it wouldn't.
Now from the side of the "rescue party". Right now the easiest way to rescue a hostage is to just kill every single hostile there is because it works. Rescuing your friends is so easy when no one is expecting an attack but once they are alerted via negotiations the safety precautions will be much higher. If anyone in my group gets taken and I want to rescue them I will not negotiate, I will not reinitiate I will simply use the KoS rights I've gained.
For a long time, I was thinking like many in here do "rp over pvp in every scenario" but back then I was campfire rping most of the time. Once you start getting in these situations you realize that it's not that black and white and what makes sense, in theory, is utopian in practice.