Joined a random posse last night and the leader was in the tailor in Blackwater so I decided to browse the catalogue too. Upon returning I got a notification that my horse had been killed, I checked the map and saw there was only one other person in Blackwater. I went over and killed them only to discover they were AFK, strange I thought but oh well.
I then went to help the leader of my posse with a mission they had started when they decide to turn on friendly fire and shoot at me mid mission as I'm trying to help them! We got attacked by a rival posse mid mission so my small brained friend actually stopped and assisted me briefly. Slightly annoyed by my leaders actions I go to the shop to restore my ammo when bam same thing again; "your main horse is dead". Then the penny dropped, my own posse leader was the one who killed two of my horses.
Words can not express the great vengeance and furious anger that I brought down on that fool, he even got a friend to assist him at one point and they both got owned over and over in a 2 vs 1.
This is about the 4th incident like this I've had in as many days. Good job trolls never seem too bright, nor particularly competent at pvp.