I kind of follow this, although with a few addenda:

-If there is more than one of the opposite faction around, and I've got some objective to take care of there, and I feel like I can win, I'll use whatever advantage I have. I want to get my quests done and get out of there. If that means rocking out some poor lowbie green-clad mage, I'm going to do it. (That said, you're generally right about questing areas - live and let live. It's more like we're all doing our grinding, and can't be bothered to pvp).

-The other thing is that if I see someone and I think I can take them, I want them to make the first move. I want that rogue to open me. I want that warrior to charge. I want them to get the first shot, so that when I pound them into dust, they'll know it wasn't just from me getting the first shot in.

I also play it by ear, but my rules are much more lax and more like suggestions:

1. No killing during an escort quest.

2. No camping unless I've been camped (and even then it's short term at best).

3. If it's with someone in "my area" but I don't want to really start a fight, give them a "warning shot" (something that'll scare them, show them I mean business, but by infrequently attacking in an obvious manner, lets them know that they need to move on).

However, this is also based on server health. The alliance on my server were dying at Cata's launch, so my guild discouraged world pvp just to give the chance for the alliance to thrive a bit. If they started a fight, we'd bring enough to fight back, not massacre them (most of the time). However, when they started to pick up but, overall, not pvp, we came down on them hard, including lowbies so they would bring their main/friends/guildies. The overall goal is to keep world pvp alive on the server, rather than get my jollies (unless it's chain deathgrips across zones- that's just fun ^_^ )

These are my rules:
1. Rules depend strictly on the class im playing @ the moment.
ex. Paladin, Warrior, Death Knight (With these classes im very "honorable", i never attack anyone unless im attacked first, mainly because they are all tanks and basically attacking me is like attacking a concrete wall...i'll crush you no matter how hard you come at me)
ex. Rogue, Mage, ShadowPriest (These classes were bred for only one purpose....assasination) Policy: Stab/Freeze/Blast first, ask questions later (usually the question being : U MAD BRO? LOLZ?)

Because I play on a PvE realm my rules are simple:
If you flagged yourself for PvP then you get exactly what you asked for at any time. I dont care if your half dead already from fighting the mob, you asked to be attacked by flagging PvP so I'm going to oblige you.

My rules - simple - I hate PVP. Unless forced into it - i wouldnt initiate it, even if there was an easy kill. That said, if I am protecting a guildie or friend from a larger pack of people, I will do it, and surprisingly effectively. Lastly when I was doing my For the XXX - I would pvp then - as people defending certain bosses would come in, to find I was waiting for them. I one shotted 12 people in a row that way.
So my rules are in defence (of others who are out numbered, or guildies, or friends) or
During achievements
I dont gank, camp or ambush in any circumstances EVER.