I found two horde that either abused exploits to kill people in Gadgetzan or killed the Alliance flightmaster:
Here we see a ?? Undead Rogue "Twinkage" fighting the Alliance flightmaster (behind the mage) in the middle of Gagdetzan
Here we see the end of the fight with the flightmaster dead and Twinkage sheeped by a random Ally mage (too little too late)
And finally here we have ?? Undead Priest "Makaal" who was using this exploit to kill random passersby and afk'ers without the guards attacking him.
These are illegal to do on Nost, right?