Don't be a dick.
You may only kill when raiding, counter-raiding, under airdrops, and in radtowns/monuments (anything with a text label on the map).
Maximum group size is 4.
No griefing or taking over a base.
No placing traps outside your walls and no placing turrets that can shoot outside your walls (even when raiding, at an airdrop, or downed helicopter).
Approximately 24 hours before wipe the purge starts. You'll be given mass amounts of food, weapons, and explosives and can basically go nuts. During purge there are no rules so destroy, kill, and cause general mayhem to your hearts content.