Combination of both, though individual friends are never "official", and often they might be friends with one or two KGB but fight the rest.

Friends are encouraged to join KGB or join a friendly tag.

Most people on a modern pvp server are hostiles, and I try to keep the friends list small , let alone think about trying to keep a listed of dozens of random friends.

That does not mean you will usually find KGB killing everyone they come across , because we dont. But, we reserve the right to do so. Generally I dont worry about people dying in a PvP game, and I dont do entangled personal politics.

If someone really wants to be friends they will join or join a friendly guild or get their guild to try and establish relations. If they wont do any of the above, its because the rest of their friends are enemies, and they are only friends out of convenience or with one or two KGB.

For DFO I am modelling more on EvE than anything actually, when I look for recent precedent and clues in establishing policy. Eve = open pvp sandbox game with territory, just like DFO. It might play totally differently in the character-level mechanics, being in space and all... but the guild/flagging/territory/ownership/etc are all very similar.