14.5 WHEN TO DECLARE AND DEFEND IN COMBAT

Syntax: 
  DECLARE <target>
  DEFEND <target>
  PK DECLARATIONS

The DECLARE command will declare your intent to engage in hostilities with that person. It is a silent command that your target does not know you have executed. It also does not require balance nor consume it, etc. This is only to tell the system that you intend to engage in hostilities against the person. DEFEND tells the system that you wish to defend that person against attacks by others. Both will last 5 minutes. Their timers get refreshed as you attack, so you do not need to worry about them expiring in mid-combat.

If you have PK CAREFUL on then it will prevent you from attacking anyone unless...
 o You have declared intent against the target (you are the aggressor)
 o The target has declared intent to attack you (self-defense)
 o The target has declared intent to attack someone whom you are defending

Note, you can only defend people whom have marked you as an ally. (It must be a real ally, not a lusted ally.) The exception is if you are the champion of your guild, a guild protector, or a member of the guild's security forces. These people can defend anyone else who is in their city or commune regardless of ally status.

So here's the kicker: if you kill someone whom you have not declared aggressions against then you *will not* get classified as a suspect or get vengeance against you or anything else like that (including curses); such slayings are assumed to be in self-defense or in defense of a friend.

If you have PK CAREFUL off, which generally is an all around bad idea, every attack you do will be considered a declaration of intent to kill someone. With PK CAREFUL off, this protection is not available to you. The only negative impact I can see this having is if you summon a friend as a favour then you have to DECLARE against him since there is no way to tell if you are summoning him to kill him or help him. So make sure you trust whomever you summon.

Note that there are ways in which you can automatically declare hostilities against others. If you defile a shrine then it is considered an automatic declaration against all members of that shrine's order. Similarly, if you attack city or commune guards, or any other denizens loyal to a city or commune, then it is considered an automatic declaration of hostilities against all members of that city or commune (or more specifically, all members of the city or commune are now defenders of the denizen you attacked).

Lastly there is the PK DECLARATIONS command, which will show you all declarations of hostilities you have as well as people you are defending.