We're talking about social sanctions against undesirable behavior, whether it's stigmatizing or something with more teeth. Prior to the adoption of Jack Kerouac morality as a proposed social norm, there was relatively little (and quite manageable) incidence of the things I mentioned. Girls weren't expelled: they were educated in Girls' Homes across the country. I'm aware of three within 35 miles of Brigham City, where I did most of my schooling, in Mantua Valley, just south of and still visible from the highway, an old house a couple of blocks from Logan High School, and one up Logan Canyon. While there were exceptions where girls simply dropped out of school altogether, most girls tended to take advantage of the girls' home option. She needn't face the cattiness in the hallways or the catcalls and imposed misery of the social sanction. Was it tough on the girls? Of course it was. Was it effective in enjoining (to the extent something can be mandated by such actions) bastardy? In the main, absolutely yes.
Was it cruel (SSS's objection)? Certainly less cruel to the first-born children of nearly all girls: they didn't have to worry about almost assured poverty, disease, crime and abuse. I must be cruel, to be kind. Freedom of bad choice must often give way to socialization. The sanction of stigma or other, more intrusive injunction, never removes freedom of choice. It simply makes the consequences very clear, and the embarrassment and shame resulting therefrom are very useful in encouraging right choices.
The result of their loss as educational and injunctive strategies is the horrors that our children and grandchildren are now facing.
We do them no favors by what we're doing now.