There is a block wide safe area at spawn. Outside this area is a full blown free for all!
No client side modifications that give you an unfair advantage (fly/speed/clear textures) or you will be banned indefinitely.
This (obviously) includes inventory editors and duping.
I should probably also note that the server runs quite a few plugins I developed myself to allow staff to monitor almost every aspect of the server. We ban a lot of people every day and you will be one of them if you try and break the rules. So rather than ruining other peoples fun and wasting our staffs time join us in the fun and follow the rules.
Other than that you get Diamonds when you VOTE and you when you join the get a diamond sword and 3 Diamonds.