School only covers part of the day. You don't always see all your friends (some share different class schedules). This doesn't cover the weekend. And it doesn't cover changing plans or adhoc after school plans.
I just don't see how someone can be shocked that their daughter couldn't make plans after they took away the prominent communication device everyone uses. It isn't like when we grew up and you'd call the landline or get on your bike and knock on your friend's door.
If all of them are close and regularly reach out with those methods normally maybe your child isn't as well liked as she thinks, then.
or they simply don't act the same as your sample size of 4.
I don't see how anyone can be shocked that taking away how people communicate leads to less communication. I really don't. Whether it's right or wrong or worth it is up to you and what you think is best.