No problem. Instrumentals aren't part of our usual repertoire, but we could certainly make a few up as we went along. We set up in the reception area, turned way down, and did our thing while guests talked and nibbled on hors d'oeuvres.
After an hour, the guests moved into the main banquet room and we packed up, proclaiming the event a success. We did what we were supposed to, which was lend the reception a touch of class while not making it impossible for people to hear each other. A few people even said they enjoyed the music.
Today I thanked the coordinator who hired us, and she sent a note back saying that we were "a huge hit":
Thank you so much for performing ... Since then I've heard MANY MANY MANY nice things from those attending the event.Wow. Even at a pure atmosphere gig, you never know who's listening.