The rules in the west haven't really changed much (and to be fair, Wilco and I are still working out the specifics - some of which may come about as a result of observations).
Basically, the jist of it is:
1 - the 'green zones' are there to make it absolutely clear to noobs and non-rebel civilians (often one and the same thing), that RDM is an absolute no-no and will get you BANNED from the server permanently (subject to the usual one-off unban appeal via the forums which may or may not succeed).
2 - as it always has been, ANY civilian (non-rebel) carrying a weapon in open view (on his back, in his hand) runs the risk of being reported, observed or otherwise classed as an RDMer, without even having to fire a shot, if he is in one of the green zones. An unwarned ban may follow, if admins are around and spectating (or as a result of reports of actual RDM, if it can be quickly established that the perpetrator is a non-rebel civilian and carrying a weapon, via the admin tools we have available now). The only rider to this is a robbery, in which a weapon may have to be carried in order to pull off the knock-down... but that will usually be obvious, and if the robbery escalates to an execution (especially without any roleplay) the perpetrator is basically still an RDMer and will get banned.
3 - rebels (with valid rebel-membership) are NOT likely to be subjected to the 'instant-ban-on-sight' if they are carrying a weapon in the green-zones, (again, assuming admins are able to determine this via the in-game tools quickly, or if the person is known as a genuine rebel). However, if they have weapons on view (over shoulder, on back, in hand, etc) within a green zone they are guilty of a crime and if caught by police, will most likely be fined and/or have the weapon confiscated. The trick here is to not get caught: obviously, if you are a rebel, possess a big rifle that won't fit into a backpack, and are shopping for food/gear/clothing/licences in a green zone town, then you are a bloody fool. Do that kind of shopping trip in the red-zone, and face up to the risks presented by other weapon carrying-nutjobs like yourself - or (for the time being) find a smaller western town to visit which isn't in a green-zone (but bear in mind you may not be able to spawn there, and may have to spawn in a green-zone with weapons out, so maybe it's not worth the risk?). On the flipside, if you are in the green-zone with the intention of dealing drugs or contract-killing a cop, then subterfuge is your watchword. You most likely WILL have a weapon out, and you must be careful to avoid detection or you'll be subject to police attention - BUT you must still be incredibly careful to roleplay any engagement in which your weapons are used - or else you will risk a ban for RDM. For example, gunning down cops that you happen to see as you trot into the Kavala church to flog some ganja, will not be considered 'roleplay' unless those cops have spotted you, warned you to drop your weapons, elicited some kind of verbal response from you, which then escalates naturally into a running firefight. You should NOT be looking to shoot-to-kill on first shot anyway (you really want to add MURDER to your list of drug-charges?) but wounding a cop on the first shot, as a warning to him, in response to his challenge to you, would be considered fair-play, and probably buy you the time needed to make good an escape.
The only other situation where rebels (plural) will be armed and in a green-zone is during an admin-approved attack on one of those cities, at which time, roleplay is considered a given, as a full-scale riot/attack/war is in effect. Rather like Sofia last night (which we hope to repeat quite often now, given that the concept has been established and worked rather nicely).
So. I hope that covers most of the wrinkles. The main intent is, as I said, to make it easier for the idiot RDMers to be 'weeded out' of the green-zones more simply. And to provide those same hotheads the scope to 'get it out of their system' in the red-zone, if they really want to cause havoc. As admins, we will NOT be compensating ANYONE for losses suffered in the eastern red-zone as a result of RDM, VDM, indirect fire, crashing whilst fleeing, etc. The red zone is DANGEROUS... It's where the loonies live. It's the frontier. It's where the cops rarely go - and if they do go, they go in numbers, and/or they go in toting weapons and with hair-trigger fingers, on a hardcore operation to extract a hostage or a wanted criminal that's worth the increased risk.