Yeppers!   Ren Faires are fantasy fancy dress event. There's a lot of crossover from the Medieval Society for Creative Anachronists too, as Scadians find them another outlet to sell their goods, which helps fund playing in the SCA. SCA is moderately more authentic (remember Creative is part of the remit).

Really RFs and SCA events are just a bit of fun and if History teachers are put off by the rife inauthenticity, then they should just not go and avoid the cringe factor. But it would be better, to encourage students' attendance with a charge to find what is and what is not "period." Might just light a fire of interest in history in some kids who otherwise would never give a second look.

Did for mine. My daughter Andie started SCA at 15 and was apprentice to a Bard. It was a big deal to her and she was what I called a snob, because she was uber keen on authenticity. Which means she was studying and researching to make certain her garb, her music and any other activities she partook were correct for her persona's place and time.