That is from: viewtopic.php?p=35832#p35832Underdark players on the surface, and surface players within the tunnels of the Underdark, who have been identified are considered to have consented to PvP
That is from: viewtopic.php?p=35832#p35832A character who continuously provokes, slanders, bullies, or offends another character is considered to have consented to PvP with that other character. The offended character is not required to give an RP out before engaging in PvP with the aggressor, as long as the attack occurs during the offending.
In theory, nothing in the rules prevented you from trying to slaughter them. But then again, I have had my share of PvP on this server and those PvP rules are pretty much meaningless when it comes to DM interpretations of the PvP situations.