My DC are older now (thank goodness I say) and this reminds of a phase DD went through wanting to dress in quite inappropriate for the occasion clothing. Things along the lines of short shorts for school non uniform days etc. (she had them for beach/swimming wear). So she was told she isn't going to school dressed like that. Of course a few words were thrown my way and a bit of a sulk ensued. She changed outfits, probably tried it again a few times, and again changed when she didn't get to leave to go to school dressed that way.
Fast forward some years and not that long ago she thanked me for stepping in and laying down the law. In with that was her discussing her horrific eyebrow choices and really cringed looking back at photos. And even said, why did you let me do that to my eyebrows. They were so bad.
Children push their luck. It's a rite of passage if you like. And then it is for the parent to step in and discourage the behaviour. Really it's just parenting, Our only job in that role, is to get our children to be functioning adults that can cope in the world.
So when a child comes out dressed as a wolf in the morning, where is the parent? All fine to wear wolf clothes to a party or wherever it's acceptable. But I am going with these children have not been subjected to that uncomfortable moment where the parent has said, hey up, no you aren't going to school like that. And it's spiralled. It's is okay to hurt your child's feelings from time to time. How will they learn otherwise? All this, 'well their feelings and thoughts count as we take our cue from them'. Yes they do, but where is it going to end?
Our job as a parent is to raise a child to be able to function into adulthood. I'm repeating this I know And by god, at times that is not easy. How are these children going to go into adulthood if they will only do whatever they want to, and not be able to pick up what is acceptable, and what isn't.
If they want to join in the fetish community as adults, that is all fine. They are choosing that path using an adult brain. Kids don't have adult brains, that is why the responsible adult is there.
And yes is agree with pp, that parents won't be aware of the fetish connection here. It is beyond scary.