While on this subject, I was once at a 4-5 day football camp held at a FCS school over a decade ago and the final day of the camp was a Sunday.
A private Catholic school from out of state was one of the 20-some schools that had came and come Saturday night, they packed up and were out of there. When we asked the coaches and players running the camp what happened they said "oh it's a Sunday, they're not allowed to miss church for an athletic purposes if it's avoidable, so they packed up and went home"