I'm rere-reading the Anne of Green Gables series, and one of the characters in Anne's House of Dreams is described as eschewing the fashion for hat pins and instead keeping her hat attached firmly to her head by a rubber band, like her mother and grandmother would have.
This made me wonder, how did hat pins work? I can use hair pins (or a pen) to put my hair in a bun or a French twist but that relies on inserting the pin in the opposite direction and then twisting it back to get the tension. I can't visualise how you'd do that with a hat in the way.
And how would a rubber band work? In my experience rubber bands are a jolly nuisance with long hair.
(Okay, it doesn't need to be Canadian women exactly, I'm pretty sure I read a Golden Age murder mystery or two where an English woman stabs someone with a hat pin.)
This one is, partly, rather simple. Hat pins were quite long- four inches or more, which is why they could feature as murder weapons in mysteries ( though, I don't know what specific mystery featured one). Until bobbed hair became a fashion in the 1920's, women's hair was left long. Girls could leave it down, but older women put it up into a bun, and that was what the hat pin impaled to keep the hat on the head.
The only way I can imagine a rubber band being effective is if it was applied around the crown. That might work for a soft felt hat, but it seems as though it would quickly mangle a straw one, so there's perhaps another angle we can't see.