If I were ever to make a "show quilt" then I might not wash it, provided it already looked great. Or I might wash it and then block it, which is what I suspect is done with many show quilts. But I don't make show quilts, although I do put most of my quilts in the local guild shows (because the guilds need lots of quilts to have a good show). I can't imagine not washing these quilts when they're finished, because they're full of starch and have been handled to death.