People are really weird sometimes about what they think is trashy looking. I buy my daughter skinny jeans because she's tall and skinny and they're long enough and don't fall off her. They don't look trashy on her. I'm thankful they exist. And someone one time posted that sequins are in and of themselves trashy. So if I buy a modestly cut top with sequins on it, my dd is dressed in a trashy way? I don't buy it.
Padded bras are made for pubescent girls because they mask the breast buds more and some girls feel they are more modest. I know I did at that age. And two-piece suits are easier to get on and off if you have to go to the bathroom.
I really think we project our own assumptions on some clothes.
Also, most kids, male and female, are sexually active in their college years. Regardless of how they dress.