I found a great way to unofficially enforce the DO NOT TOUCH rule at quilt shows: I bring my own white gloves. As I wander the quilt show, if I see someone touching a quilt, I go up to them and ask if I can turn the quilt for them. They assume I'm a White Glove lady, but I very gently make a point of telling them that no, I just know that it's against the rules to touch the quilts, so I bring my own.
You can buy white gloves at your local pharmacy for $2-$4.