I am a Mormon. Live in the Salt Lake area. These preparedness fairs are pretty common. We have one each year and my 72 hour kits have been displayed there frequently.
The philosophy is to be prepared for the benefit of the family. That preparedness may come into play from a natural disaster or a personal disaster. I knew a family where they lost their employment and were able to live for months on their food storage until new employment was found.
The preparedness focuses on "at least a 1 year supply (of food, clothing, hygene items, etc.) to provide sustinance." And, as in the general population, not everyone is prepared for this so there is the philosophy that if we can get people to start with a 72-hour kit, it is a start and they build from there.
As far as the cannery (that is what they call them), they are part of a welfare system that the church has. Typically, they ask that you volunteer to work in the cannery and then you in turn can purchase the items that are canned.
They have 2 types of cannerys: dry-pack and wet-pack. In the dry-pack, dry items (e.g. sugar, dry milk, flour, potato pearls, dried fruits, beans, etc.) are placed in the #10 cans and sealed. I don't think they'd let you bring ammo in and can it (pretty sure they would not allow ammo in the food prep areas). But they do have a loaner, crank operated machine that seals up the cans. This can be borrowed and taken home so that you can do some of the canning at home. I've actually considered getting it and trying to "can" some ammo. As far as I know, they do not do beef stew in the #10 cans as they have no way to process (i.e., heat) it at the dry-pack. They did let me seal up an empty can once which I gave to my dad as a can of "dehydrated water". He got a kick out of that and still has it with his food storage to show off.
At the wet pack cannery, they do things like chilli, beef stew, jams, salsa, etc., but they usually do these items in smaller (14.4 oz) cans or in pint bottles. The wet pack is located at an entirely different facility. We (my wife and I) have both spent time in the canneries and use the items from there everyday as it tends to be a little cheaper than the grocery store. I actually have a can of chilli and 2 cans of beef stew right here in my desk that I helped can at the cannery. The work there is not hard, it is kind of assembly line and you have one or 2 tasks that you are asked to do. Pretty cool process really.
I'd suggest that you go and check out the preparedness fair. You may be able to find out about volunteering at the cannery and be able to take advantage of that. You may get some preparedness ideas although they seem to be more along the lines of getting people to start getting things together rather than for people who could already last 2 years and teaching them to stretch it into 5.
As far as the Mormon community goes, we seem to be pretty close knit. The Church provides a social structure that we rely on quite a bit. There is an emphasis in the Church for missionary work so proselytizing takes place and unfortunately some members become overbearing with that. Generally though, anyone is welcome to attend these type events, and any of the Sunday meetings for that matter. Good Luck.