I had a great time reading this thread.
Although it is a thread about counterfactual elements, I think that the positions of many forum users are crystal clear.
I believe that this law would have many problems on a day-to-day basis, but if I work with my imagination a bit, I think that in theory, it is positive.
In my opinion, I think that a reasonable age limit would be menopause.
Although I see it as correct that the law was limited to unmarried women, in the end I believe that married women would end up wearing belts. First, some husband would not like his wife to be one of the few options for other men, and, probably, if she wears a belt, either because of pressure from husbands, or because of women for not wanting to appear "women easy", in the end it would spread.
And also, even if it's half in jest, it's okay for married women to wear it because that way, if they want to put their husband's bags at the door, they do it without thinking that it will mean wearing the belt.
I liked this thread, very well run, and without reading the sad things that are sometimes in others.