Office family day on a Saturday. Worth taking a 4 year old to see where I work?

My office is holding a family day next Saturday: games for children, a magic show, and parents can show their kids their desks. Our daughter asks most mornings where I go and why it takes so long, and on release days she has started saying 'your office' the way other people say 'traffic'. Part of me thinks seeing the place would help. It becomes a real building with a chair she has sat on and people who know her name. The other part worries that she will spend two hours in a crowded cafeteria, get overtired, and come away with one more reason to dislike the place that keeps me late. My partner is on hospital duty that day, so it would be just the two of us. Has anyone taken a preschooler to something like this? Did it change how they felt about you going to work, or was it just a long Saturday?