I'd like to see this system implemented in The States. It basically circumvents the school yard bully from stealing lunch money from would-be victims.
The only thing that can (and will) circumvent the school yard bullies from bullying is this.
Self-defence is, always, the best defense.
Oh, the victim overreacted? Educate him/her , punishing him/her for force abuse if it's the case. BUT NEVER punish the self-defense.