300
As your class is lining up after lunch, one of your students is swinging his lunch sack & accidentally hits another student in the face, leaving a small red mark on their cheek.The student swinging the lunch sack immediately apologizes to the other student, who although startled, is not hurt, & accepts the apology & says he is fine.
What is a note home... or better yet ...What is a phone call home? What is time to go see the nurse?
(This is also just good public relations and communication)