In our school district, if that happened, the driver would report it after arriving at the school and the kids parents would be held responsible for getting them too and from school for the rest of the year.
The parents know this and the kids know this.
I remember kids getting suspended from taking the bus when they were caught throwing snowballs at one. I also remember some idiot putting ajax in bread before feeding it to a seagull. The bird’s stomach exploded when it began to fly and the guy who did it was pounded into a bloody mess. Not all of us were angels but rules and consequences sure helped modify behaviors.