When I was a tween I went to my first R&B show (I believe it was EnVogue). I had been to oodles of shows so I knew the uniform: comfy jeans, comfy shoes, clever T, and discernible lack of hat. But there was a secret I didn't know about EnVogue fans: they dress up for a show like they are going to the prom. They get their hair styled, they wear suits and not dresses, but actual gowns. Gowns I tell you. They complete the look with the perfect prom accessory, a limousine. Not just one couple or ten, but droves of them. Three R&B shows later I discovered maybe it wasn't just EnVogue after all. Some people get dressed up for shows.
I'm not saying you need to follow a dress code by genre system. I may wear a tutu at any time, and I support your right to do the same. But some people do like to fit in, and might like knowing this stuff. I'm just saying if you are going to a kind of show you've never been to before, it might help to ask a knowledgeable type what people are likely to wear. Because if you show up dressed for the Prince show at the Gwar show you are going to stand out, and ruin your fancy shoes.