A unique feature of early films was the projection of slides onto the screen while reels were being changed. Some of these slides attempted to teach proper movie-going manners to those in attendance.
Eager to expand their profits, early movie theaters, or “nickelodeons”, often put up slides between reel changes encouraging women to attend films (e.g. “Ladies and children are cordially invited to this theatre, no offensive pictures are ever shown here”), as theaters were not considered entirely respectable places.
As more women started attending, nickelodeons had to contend with scoundrels who tried to use the cover of darkness to get fresh with women, leading to the creation of “annoyance”, or in modern parlance, sexual harassment, PSAs.
Judging from the large number of early PSA’s directed at people sporting headpieces indoors, it would seem that defiant hat-wearers were the turn of the century equivalent of people who leave their cellphones on at the movies today.