Our local folk society had a problem a few years ago with a guy who kept coming up and sticking a mic in people's faces when they were trying to sing, or slipping them behind their chair while they were playing. Disgust and annoyance didn't deter him in the least; an article in our newsletter was ignored; we finally had to get quite blunt and tell him that he needed to ask, as some folks aren't comfortable being recorded--and others may be performing original material that they don't want 'floating around' unauthorized. It isn't hard to just ask permission--most folks will say yes, and even go out of their way to accommodate you!

On one occasion, I was at a concert at the Ark in Ann Arbor, and the performer was having a miserable time with a hum in the sound system. He finally stopped the performance, so they could go over the sound--and I watched, while he and the sound guy checked out the system from every imaginable angle, but the hum was gone, and everything was fine.
They started the show again--and there was that hum again!! At the same time, I noticed that a man at our table had turned on a tape recorder just as the hum started. I don't know much about sound systems, but, for whatever reason, this man's recorder was interfering with the sound in a most annoying way. The hum and the turning on of the recorder were too closely synchronized for anything else. I looked across the table at him, and hissed through my teeth: "TURN THAT OFF!!" He started to protest, and I hissed again: "NOW!!"

He turned it off, the hum stopped immediately, and the show proceeded, unhampered...

I'd say it's best, and easiest, to ask before taping!

denise:^)