This analogy fails on two levels. First, kids are by definition immature. This means we cannot trust them to make the right decision when it comes to use of force. Most adults are presumably mature. If they are not, then they should have court appointed guardians. Second, there is an authority here – the teacher. Kids are usually close to a responsible adult. Who is the equivalent in the real world, the police? When seconds count, the police is only minutes away.
Unexamined Assumption: Kids = Adults