The rule where you had to ask a user as to what their reason was for killing an innocent was removed a long time ago, therefore if they kill an innocent you can kill them. The act of killing an innocent player is deemed a traitorous act as its the whole job of traitors is to kill innocents. In cases like this it would be very easy for traitors to lie and say "well he was KOSed" and then go about their business as a traitor, which would be a little annoying imo. Its the players choice whether they believe things like KOSes, if as you say the KOS was in voice chat it would be very unfair if someone killed you after you killed an innocent only to be warned for it as they did not hear the KOS for whatever reason. This is the reason why the karma system exists.

The rule where you had to ask a user as to what their reason was for killing an innocent was removed a long time ago, therefore if they kill an innocent you can kill them. The act of killing an innocent player is deemed a traitorous act as its the whole job of traitors is to kill innocents. In cases like this it would be very easy for traitors to lie and say "well he was KOSed" and then go about their business as a traitor, which would be a little annoying imo. Its the players choice whether they believe things like KOSes, if as you say the KOS was in voice chat it would be very unfair if someone killed you after you killed an innocent only to be warned for it as they did not hear the KOS for whatever reason. This is the reason why the karma system exists.