Will anyone be offended if I work on a small quiet craft project during the concert (e.g. knitting/crochet/cross-stitch/hand sewing)?
I can’t speak for every artist, but in general small quiet crafting isn’t a problem. You are also welcome to listen to the concert from the adjacent dining room, if your craft requires a little more moving around. As long as your craft isn’t disruptive or offensive to the listeners or artists, then it is fine with me. Do remember that some concerts are well attended, and our house is not the largest. Any project that takes up more than your lap-space could be an issue.
