We're just going to have to agree to disagree.
It's not over reaching for the school. It is holding them accountable in their 'professional' choices. How many parents DO NOT hold their kids accountable? How many of the parents will go 'it was just a harmless prank'.. well suppose that a bowling ball had been in the back of the victims vehicle and it bounced out of the rear of the vehicle causing multiple accidents and possibly a fatality? Still a harmless prank? Not so much.. Thankfully it did not happen, but if the kids are not taught that there are consequences to their actions then guess what.. they'll do it again.. and again.. and again. Until such a time as there are real consequences, then what do the parents do?
I'm not saying GG isn't going to find an acceptable punishment for his kid.. but this is another layer of it. She was suspended for a game.. it's not as if she were suspended from school, that would be over reaching. Suspension from extra-curricular activities is not.