Really? You never went on an school trips overnight or camping stuff? I dunno it does sound a bit odd, but I remember going on 3 day camping trips…and even overnight trips for school competitions etc. It was co-ed in the sense that boys and girls went, but we slept seperately.
We used to go to this Camp Burney and all the girls slept in 1 cabin & the boys slept in another cabin and the teachers were pretty vigilant in making sure nothing happened. Overall we knew the rules and most of us adhered to it. Then again the camp trips were offered as rewards for those who get honor roll/credit roll…so dunno