You should tip them just like you tip counselors. Its just proper and shows appreciation. The boy slaved away so your son can eat 3 meals a day. The waiters work VERY hard and are the most under-appreciated people in camp.
I cant tell you what to do with your money but realize that if you didnt tip in a restaurant the waiter would not forget you and the next time you came to that restaurant hed make sure something nasty ended up in your food.
Its just low class not to top. Especially a camp waiter who slaves away 3x a day every day of the summer for your child.
You are Karging out on $35-$40? Seriously think about it. The tip in some fancy restaurants are almost that for one meal!