It's a hard situation to deal with when parents are fighting over custody of their children. When the school is involved, that's even more difficult. The staff at any school with children involved in a custody dispute need to know much about the situation to make sure the staff doesn't make errors.
The most common issue for parents is a lack of access to school records. Just because a person is a parent it doesn't mean he or she does have access to those records. If the court did not grant the right to obtain school records, the school shouldn't hand them over. Likewise, if the court didn't forbid it, then the school should release those documents in accordance with the law.
Another issue schools have during custody disputes is with communication. Is calling one parent enough when there's trouble at school? Will the parents communicate? The most likely answer is no, so the school needs to make sure to reach out to both parents to give them the information vital to their child's care and educational needs.
Finally, if a parent doesn't want the other to see or pick up the child at school, there has to be documentation. Schools need to request copies of custody orders up front to be proactive in the children's care.
If you and your ex have not settled your differences or have special requirements for your child's care, you need to make the school aware of those issues so that it can take appropriate action. If you don't, the school may make mistakes that could result in upset for your family.
Source: Campus Safety, "How Schools Should Protect Students from Child Custody Disputes," Amy Rock, April 23, 2018