Please read what I said: "The backing" from surrounding musicians and percussionists - I wasn't selective.
Maybe some of these "Teachers" at festivals and work shops could teach a bit of etiquette and good manners - You claim to do this well done.
I'm sorry but if someone was asked not to play (for whatever reason), and then their spouse further added to the problem by joining in, is just pure bad manners and to my mind should not have to tolerated.
re. "What about the self appointed rule makers who welcome newcomers who show huge talent and reject the ones who don't conform to their ideas of proper behaviour"
I'm not sure I can compare Talent to behaviour - I personally think a talented musician with bad manners is as bad as anyone with bad manners, talent doesn't negate bad manners.
I presume when you are teaching, you have some class rules, expect your students to have consideration for other students and they don't all bash away in their own tempo at the same time, or when you are trying to show them how to play?
If someone had been singing a different song at the same time as Raggytash in a different key and at the top of his/her voice would you think that was alright?