Personally I think its great to get local flavor in our game from other chapters. I might have a skewed opinion based upon the travel that I do, but when I went to Gettyburg and saw the Red Back Spider tribe, I wanted to play an elf. The local flavor of that individual packet aside I think it would be great to have one of my players reach out and bring another chapters unique vision of a race into our game.
From what I have seen it has mostly been fun RP hints to play off of, and histories to make your character more fulfilled. I.E. Instead of being an Elf who grew up Elfing and doing Elf stuff, now you are Sylindar the bottle maker from The Ebon Jungle. Your family had long been a part of the house of broken reason, but you had other aspirations and struck out on your own through the mists.
These types of things when handled with care create great and dynamic characters who might someday interact with other people from that culture at things such as our national events or one of the large regional gatherings (The Ball in Denver this weekend, or Big West for example [shameless plugs, I know]). Also over time your character might naturally move away from their home packets. My primary for example started as a Selunari in Andar (Seattle), less than one year in and there was a plot line that locked everyone out of Andar, and severed all of our connections to our homelands....now the character is primarily played in Oregon, Gettysburg, and Asheville, none of them even remotely close to the characters originating tribe or personal stories.
I think the biggest part of playing from a culture packet of another chapter is to come in with the expectation that you will not receive culture specific plot outside of the chapter that plot is written in. If the plot team wants to go out of their way to incorporate it, or maybe some big cross chapter plot happens where a culture migrates into a new land (see Stone blood tribe of Orcs in Seattle) then it is a bonus, not necessarily the expectation.
I think one of my favorite things as a world builder is to see what players do with what you have put out there, if you look at the Seattle packets and think to yourself, this is horrible why would anyone ever play this, I probably wrote it! Then when I see people play something from that packet I am like YES!!!!! that is so terrible! This is great!!!! I want that out there in your games! That is why I play alliance. I want to infest your game with my garbage elf who licks everything and solves conflicts through feats of strength (just elected a noble in a foreign land with a physical contest)
In the pacific NW we have a rediculous amount of local LARPS. Everything from playing a munchkin on the yellow brick road to jedii (I dont know what the plural is), to space marines with NERF guns. Every one of those games is self contained. In games like those I would absolutely agree about keeping things secretive and held under lock an key if you want to create information scarcity as a theme. As for Alliance though, the entire point is to play in a game world that meaningfully interacts with other game worlds. It doesn't have to be the focus, but it is the expectation. There are many other continents across fortannis and ~ every other year a number of us take a break from saving our own continents to all band together to stop something calamitous from happening to the whole world, basically we are the Dark Ages Avengers (Dibs on Ye Olde Hulk). Its at times like those that finding a group of people from a culture kit you are a part of, but havent been able to interact with, could make for a mind blowing experience, not just for you, but for all of those players as well!!! [I have a comma problem]
I would be ecstatic to find out there was a stone elf out there from our local trident, do I care that the person might have to make up some small details? No!!! Maybe they are just misleading everyone so they don't find out the truth!! (Which is funny because if you have ever been on plot with me, I am the first to say we cannot do something because one time three years ago this one thing happened and doing it this way now would not make sense!) Irrespective of that it shows that the work that I put in is worthwhile, and their use of it validates the time spent twisting and squeezing every last idea drop out of my brain. This is one of the reasons we chose to produce and host our local culture packets openly. Then if a player from somewhere else has a question, we are always available to help answer.
I remember my very first game, I showed up so confused, and was already commited to a character, then after I started playing it I received the local culture packet... It just didn't fit anything I was playing or going for, I mean parts of it did, but for the most part, it wasn't what I wanted to play, everything about it was too neat or special, and I viewed my character as a simple wandering hobo. if I had access to other lands cultures I think it would have been epic to roll into Barran 20-30 levels later and be new, but familiar, like a homecoming of a long lost cousin or uncle. To me that not only builds RP, but also builds on the idea that all of our lands actually ARE interconnected, and sometimes regular people and NPCs will trave to other lands! That is what excites me about a live conjoined world, and why I think having a repository for culture packets woulld be a positive thing
This doesn't just go for cultures, but really for anything. If Wellorg decided to Floow his buddy Luke home to see what the Ceriopolis was like, I would find that great!!!! Look everyone, Luke brought home a Dragon!! Or a highwayman hitched a ride to Sedovia on the back of a Juggernaut, it would be amazing, and just add to the world toolbox that the local plot teams can pull content from.
Now that I've said my two cents, don't look at me, Im a monster, argh!
-Tony