I've got no issue whatsoever with things like putting hats or sweaters on snakes. Not my thing, but it causes the animal no harm, so for those who enjoy it have fun, I'll probably even "like" your pics if you share them./
Wouldn't stress be considered harm? I'm not saying that costuming snakes is inherently stressful to them, but I can imagine it often would be.
1.0 Link, my Abbott Okeetee corn snake
1.0 Pit, my Yellow-belly ball python
1.1 Ramza and Midna, my kittens