This isn't legal advice, just from one parent to another. I think this is great! You should get out of your car every time you pick her up and march into that office happily to sign her out. Pick up whatever flyers/newsletters they have while you're in there too. A lot of times the office has more info available than they actually send home with the kids. Make sure you say hi to everyone that works there as well!
What child doesn't LOVE to parade their parent around the school proudly? I always love going to the kids' school-I want to make sure that i'm a familiar face there and that the teachers/office will WANT to contact me if they need anything. You are lucky to be able to pick her up from school-a lot of parents have conflicting work schedules and such. I bet it makes her very happy when you pick her up.