Some rules clarification

So there are many people who wonder about details of ban reason for like disrupting gameplay, so I personally would like to ask about some rules that I don't fully understand (I will be relating to official code of conduct from here http://forum.warmane.com/showthread.php?t=65037 ):

1) PvP in Sanctuary: People shouldn't be able to attack others in Sanctuaries, like Argent Grounds and the entrance of Forge of Souls/Pit of Saron instances. Forcing it through magic is not acceptable.

So regarding to this, what does that actually mean? The PvP is off inside sanctuaries so does it mean you do something like in Runescape's falador massacre where players could attack people where pvp was literally impossible? I mean players going inside FoS/PoS gathering place are coming from PvP enabled zone and when they go outside they leave the sanctuary area and are in PvP enabled zone. So is it okay to kill them? Is fighting next to it forbidden or it's just about inside place where is summoning stone, entrances to dungeons where PvP is disabled and someone would have to bug his way to be able to attack them there?

2) MMR Dropping: Losing in arena on purpose to lower own MMR below normal value.

I'm pretty sure it was stated many times by official staff it was not punishable. Can it lead to a ban now?

3) Is killing people leveling (no matter how many times or where, sholazar basin, STV or wherever) allowed or it counts as disrupting gameplay just because they are killed even tho they are in PvP enabled zones?

@EDIT 4) Is sitting inside Dalaran bank on flying mount (there is way to be one there) where mounting is not possible considered punishable bug exploit, even though it doesn't really affect gameplay or any players?

Ty for answers..

1) Yes, that's it. You can fight them in front of the entrance. But if you find a cool bug that allows you to attack them inside then you should not abuse it, but report it on the bugtracker instead. It's basically a no-exploiting rule.

2) If it's in the rules it's punishable, I doubt they'd forget to update the post when changing the rules.

3) It's completely allowed, maybe if you camped one guy for like 3 days you'd be banned, but I doubt anyone's that persistent. It's more about constantly killing the quest giver NPCs, city folks and such, but even then it's not really disrupting until you keep them dead for a very long time, at least to my knowledge, didn't push my luck.

4) I don't think so, it sort of is an exploit, but it's a victimless one. Some players have crappy latency so they can't even control it, I'd say you're safe to show off your mounts just like the rest of us.