Opposing guilds should have the ability to declare war on eachother which would enable them to attack eachother in any %gas zone.
Reasons:
1. It would be fun and voluntary only.
2. Something for high level players to do other than level like zombies
3. Provide a tiny change to ROLEPLAY
4. All basic pvp rules would still apply, aka level restrictions(equal)
5. because pvp in this game is so lame and for guild wars to exist they must be fought in 25 or 0% zones where other people could and most likely will interfere.
Explanation for the Rpers:
"The sight of there hated enemies sends guild members into a rage defying all constraints of happy gas."
Tell me what you think.
Also have allies would be cool too, and alot of this is based off of UO pvp/guildwar system which i think is very good.