You guys crack me up!
Huge open jams can serve a useful purpose - but they are definitely not well suited for ALL purposes.
I live in the western suburbs of Chicago. I found these guys through an on-line list. During the summer, they play at a
local farmer's market - where they have played since (I think) 1976. If you are interested, there are several YouTube clips featuring some of the "more senior" members of the group. (If you look closely, you might even get a glimpse of a handsome bassist...).
When I first met them, it was winter. Before Covid, the main group split into 3 smaller groups which had different preferences. I met up with the group that favored BG and met in a coffee shop. A small space, so there was rarely more than 8 pickers, and they were some of the better pickers you see on that vid. They were VERY happy to have a bassist and were very welcoming. It was very much of a crash course for me learning tunes and playing them to speed.
As spring rolled around, they moved back outside to the market. It is a really nice space/experience - under a big tree, the market sells donuts and coffee and has tables set up. A lot of people have been coming to see the group for years. A fun, new experience for me. I met many of my closest friends, and formed my string band with other members. Various groupings of the big group perform under various names, and for various community events.
Then Covid hit. We lost 1 year at the market and indoors. Last summer, the market had really onerous rules, so I went back to golfing Sat mornings. This fall, the coffeeshop allowed a max of 6-7 pickers - which pretty much comprised my favorite folk.
The 2-year break sorta reset my opinions regarding this group and my preferences. During Covid, my wife and I sought out opportunities to play at our highest level with small groups in old-time and classical. Now when we were able to get back in the coffee shop, I'm able to make music at a pretty decent level w/ some of my best friends.
A couple of members sought and found a larger alternative indoors location. That is where the motley crew I described played. As I've said, my opportunities to play in smaller, higher level groups has spoiled me WRT such free-for-alls. Outside 2 years ago, it is still fun. I hung w/ a small group of my closest friends and we basically made music within ourselves - not worrying if someone on the other side is paying attention. And it is nice to be outside, people watching... Also, a group of us met inside for 1.5 hrs BEFORE the market to try out new tunes, etc.
My personal opinion is that the big group places too much of a premium on being open TO ALL - independent of ability, effort, or instrument. I've discussed it with others, but the most senior members are adamant that ALL are welcome. Now it can be a kick to have someone show up with a nontrad instrument, if they are able to play along. But there are others where IMO we shoulda just said, "Find another group." And it is GREAT to play with a kid just beginning - for a couple of tunes. Some of the kids went on to win state competitions, and a couple are currently recording pros. But being overly welcoming really shortchanges the folk who are interested in making decent music.
Sorry for writing a tome, but just wanted to flesh things out and respond to some of the comments.
Hammertime3 - don't even think twice about setting down rules in YOUR space. I'd think NO AMPS would be a basic one. Tho consider whether a decent banjo COULD add something to your current group. There CAN be very great overlap between countries and BG. IME, a lot of people consider themselves BG pickers, but they really are not "purists."
In any event, if the guy shows up and it doesn't work out, don't hesitate a second to just tell the guy, "It was nice to meet you, but I don't think we're a good match."