They are okay....
I think it's kinda tacky when you can see a girls underwear or her butt crack when she's walking around in public.
I find it rather sexy when a girl unbuttons her jeans and slides them down her hips a little (PS, I like girls with hips, girls with the shape of a pencil don't interest me much), but in public I think it's kind of tacky.
But who am I to dictate her fashion to her, if that's what a woman wants to wear, it's not my concern.