Hmmm, I never really had a problem with JP. Most I talk to always respond kindly, and actually sit and try to chat..
Outside chatting, in parties, either it be camping by them, or in party with, they are always respectable..
The main thing I found, as mentioned, is you have to ask/say before you act. When I camp by any JP, I ask them if it's ok to camp there, 99% of the time, they say sure, and we help during links, or anything, if something goes wrong.
HNM's, well, never did any against JP's, lol. Serket they stood back and didn't crowd at least.
So yeah, my main advice would be to ask before you act.
Gil-sellers... Well, we all know how this is. Superstars are not awesome people. Tell that to them when they tried to MPK UC, and me, the first time I ever camped Serket.
In Kuftal, man, do they ever love MPK'ing with lizards.
Work with them, they love you. Against them, they hate you.
JP MPK'ing.. Who, is it possible they'd do such a thing? Yes.. Shikigami Weapon.. We won claim, when I was in Avatar, and JP's loaded us with weapons. Their level 60's died right in front to aggro us.. How/why would you try to MPK all SMN's? I dunno.. Sneak and carby.. Can't go wrong there. End result: Many dead JP's, and a new YY for a member of Avatar..
Just my experiences. Guess anyone can do anything here. Hard to trust anyone at all..
Will I stop by and help you if you're in trouble? Sure, just don't try to be my best friend afterwards, lol.
I love helping, and I ask for help sometimes, but it's hard to depend on much anyone outside your friend list/LS these days. Just play it smart and safe. ^^
~Nieko