Notably, the few times where she had a uniform that isn't an example of this trope other than her origin story where she was only about 13 or 14 was when it wasn't her creators Craig Kyle and Christopher Yost writing her Chris Claremont first and later Christos Gage and Dennis Hopeless so this might be due to Author Appeal. This was somewhat controversial with fans who preferred her earlier harlequin costume with no exposed skin at all except her face. It came to the point where when the third incarnation of X-Force was formed, she was the only girl in the team whose uniform had this. Gideon the cat in Pinocchio wears a purple shirt with loose sleeves that is too short to cover his belly.
Even Nightwing gets in on the act by not wearing a shirt. Western Animation in particular seems to love this, since it's an easy form of Fanservice that the radar invariably misses. The video shows Ms. Many female characters in Biohazad Heavenly Island.