<disclaimer: I didn’t read most comments on this thread>
I worked in a very well known camp for several years, as did my siblings. I personally would prefer to tip the counselors for their service based on the fact that the kids who tip are treated much better than the kids who dont, OR, the kids whose parents send in a thank you note.
I remember one of my siblings once worked in a day camp, got paid next to nothing, and got no tips from the parents. My mother called up the camp, horrified, and they said, “we send home a tipping letter, but it’s completely up to the parents.”