It's way different here. My daughter is 12 and her father and I divorced when she was 2. We share legal and physical custody, but I can honestly say I've never been asked a single question when I enrolled her in daycare, or school, or took her to a doctor. No one ever asked for paperwork or permission from dad for anything. And vice versa. Her dad is the one who took her for orthodontic care, enrolled her in summer camp, all kinds of stuff. No one ever asked for my permission either. Same with airline flights. He takes her, I take her, whichever. Only one time has anyone ever asked a question about custody or the other parent, and that is when I applied for a passport for her. They did demand his presence then, but that's the only time.
Which is kind of scary when I think about it.