Firstly, is it a public or private school?
If it is the former, I'd tell my child not to do it and write a letter to the school explaining that my child is my responsibility over the summer, not theirs. It is my job to raise my child, not theirs. And during the summer, if I want to park my kid's ass infront of a TV and feed him chocolate and candy every day, it is my choice, not theirs. When he is in their school for eight hours a day, five days a week, they can do what they want, but other than that, back off.
I can't wait to be a parents, I'm gonna feed him nothing but ketchup and mountain dew, let him play with a crossbow and watch zombie movies. I'll give him the childhood I wanted.

