At my age, pinpointing when something occurred, is sometimes tricky. My best guess is that the following occurred around the early 90's.
On a hot summers day, in Guelph, Ontario, Canada, young Gwen Jacobs was walking along the sidewalk of a busy downtown street. She suddenly decided right there and then that it was unfair for men to walk along topless while women had to be uncomfortably covered. She removed her top and nonchalantly continued her trek. In due course, as one might expect, the police arrived on the scene, "scene" being the operative word here, and promptly arrested her.
Gwen, the assertive and resourceful gal that she was, even at her tender 20ish age, secured herself a good lawyer. To make a short story shorter, the court was convinced that she was right in having equal rights to a man in regards to public (un)dress.
The effect of the case was immediate, if not widespread. In the following months, the occasional young, and even not so young, female could be seen exercising her new-found "freedom of expression", most often at beaches, parks or in one case, while watering the front lawn. Each incident that was spotted by a member of the hordes of press that were now scouring all venues they thought might yield another "Gwen", was immediately flashed across the television screens and had everyone wagging their tongues about it. Beach attendance figures broke all records that summer, attended by mostly adolescent boys (of all ages) hoping to get a head start on September's anatomy class.
Well, extremely conservative Canadians couldn't stand for such a public debacle. But what to do about it? When a "lady" of a certain age, in a small public pool, with even smaller children, insisted on exposing her ample bosom, thereby covering up her navel, enough was enough. The police arrested her and somehow managed to convict her of some sort of community standard statute. After that, one or two more incidents were reported to have occurred at the beach and that was the end of it. Canada was proud to revert back to the prude it has always been. And Gwen Jacobs was indelibly etched in Canadian history.