Dr Oz just talked about a related parenting topic today. The fact that things are different today than they were forty years ago was brought up. He pointed out a statistic that abductions really haven't gone up, we just hear about them more. However, people getting hit by cars have increased significantly.
I'm not a parent, but I was a kid and I knew squat about life in third grade. Today there are more opportunities for kids to get in trouble than when I was that age, in the 60's.
It's in the school's best interest to be accountable to the parents and keep track of the kids. They are responsible for other people's kids so they have to answer to the parents. If something should happen and they could have helped with timely information, but didn't, they could be facing a lawsuit or worse.