Why give people options like that though? If you let the PvE servers have everything the PvP servers have, why have PvP servers at all? Honestly?
As mentioned before GvG is not the same as OWPvP. They are very very different. Why have battlegrounds on PvE servers, or duels even? That's the same thing. I just don't want to be ganked while quest grinding. It doesn't mean that two guilds shouldn't be able to duke it out if they agree to it
If a member of a guild didn't like the war declaration, they can leave the guild. They always have a choice to not fight.