When I was younger and my sister and cousins would be in the nursery, an usher would come down the isle and slip you a piece of paper if there was a problem with your child. This was back in the day that the usher's wore suits, ushered people to their seats after church started, took up the offering, and stood at the back of the church for the entire service. When you went to pick up your kid from the nursery you just walked in and got your child.
When my kids were born, we were given a family number for when there was a problem in the nursery. There was a screen over one of the doors in the sanctuary and when your 3 digit number came on the screen you had to go to the nursery to take care of your kid.
Now, as I checked Joel, who is 9 and in the 4th grade, into the children's department at church, I was asked for my cell number so the teacher could "text me" during church if there was a problem.
Man, how the times and technology has changed. I also had to show a card in order to pick him up from class. What happened to just letting the kids go find their parents. This would be SO much easier on the parents and teachers. Then the teachers don't get mad when it takes 10mins to every class, show your card and pick up each kid then go to the next part of the building (or the building next door) to get the next kid.