If you start wearing a shtreimel, it doesn’t make you chassidish. But if you would absolutely love the shtreimel look, you wouldn’t wear it either, because Chassidim wear shtreimlech.
That proves that we are categorized by our clothing. When I walk down the streets, I see what people wear and according to that I figure where they belong.
A different story is if someone doesn’t live up to their dress code…