I worked in a well known day camp in Brooklyn for many years, and can provide some insight on this.
Day camps really pay their counselors next to nothing. Many are paid even less than minimum wage, and could probably file a complaint against the camp for it. They are told by the administration that they will get plenty in tips. In the camp I worked in, there were certain groups of kids who were known not to tip. The counselors who had those kids would get a bonus from the camp after the summer if they got tips below a certain level.
You can complain about the extra cost all you want. If parents stopped tipping, the camps would have to pay the counselors more money. That, in turn, would make the camp charge you more to send your kids there.
From personal experience, I can tell you that yes, there are parents who have a hard time tipping. I’ve had many times where I didn’t receive even close to the suggested tip (which, by the way, hasn’t gone up in close to 15 years – while the cost of camp has more than doubled.) However, I often received a nice note together with the tip. I didn’t mind those at all. There were some kids who didn’t tip at all, with no note. They were usually the kids who didn’t behave all summer, and gave everyone a hard time. I really held it against those parents, and still do, to this day.