Never been to one. I do know the last thing you want to do at my show is say anything negative about the music or a singer. Our small stage area is just to the right as you walk in. That's where I am located also. Something strange about the acoustics; you can hear what's being said sometimes 4 or 5 tables away. (My wife can't understand how I can hear that far with all the music, yet at home can't hear across the table. I just shrug my shoulders and grin.)
If I hear someone saying anything negative; which is not very often anymore; I will take time out to tell them "by mic" that negative comments about me are ok. Tell me your problem. But if you don't like like the music or the singer then you have an option. 1. you can't pick something out that you want to sing; or 2. find someone who will sing it for you or 3. We have a front door and a back; take your pick." This usually brings a chorus of applause.
Kelly