Depending on the incident, I don't know that I necessarily need to be told anytime the police are called to my child's school.
If a 4th-grader falls off a piece of playground equipment and they call 911 and an officer and ambulance show up, as the parent of a 1st-grader, do I need to know that?
If an angry parent shows up, the police are called, but the parent never gains access to the school and the kids inside are unaware of the event, do I need to know that?
I tend to think that, unless an incident actually puts MY child at risk, I'm not entitled to know all the details.