I would certainly hope that MOST of you have learned from this experience and will interact more harmoniously next time around. The fact that most of the above exchanges have been good-humored gives us hope...

For a band, or even a group of loosely associated individual musicians, to be "booked" to "run an open session" is almost a contradiction in terms, a situation rife for misunderstanding. Are the hireliings supposed to play their own shared material as performers, or are they supposed to provide a venue and a context where random attendees can show up and feel welcomed to participate?

Acting as host/emcee is probably more difficult, or at least a less common skill, than performing. And I would think that the role of emcee would be much more effectively assigned to an experienced individual than to any group, and especially not to a group of players who are ready, willing and anxious to play the material that they have rehearsed together, and in so doing, to make other potential participants feel unwelcome. They might very well not mean to shut others out, but nevertheless they are very likely to create such an impression.

Also ~ if the "session," or "performance-masking-as-a-session" was indeed too held close to another stage/tent/venue, shame on the organizers! No one participating in or listening to either of the competing events needs to be subjected to excessive "sound bleed."