Either actual writers who care about typography, or actual writers who have had their writings edited by a real editor. Or even anyone just curious enough about writing that they picked up a manual of style.
i'm a frequent em-dash user. it's great for little appositive clauses because it can make the sentence feel less cluttered than commas.
but i have no idea how to type an em-dash. you just put in a double-dash/hyphen (i.e. "--") and any modern word processors will know to convert it to an em-dash for you.
I suspect that lots of writers who use this trick are getting unfairly slammed with "omg, youre an AI! no human knows how to type that character!"
