PGirl is fine so long as the oval is relatively small, especially if she's wearing something nice and supportive under it. Also, bulletproof skin might mean she shifts around less than us fragile skinned mortals.
I always figure that thing Canary is wearing is a has a built in corset / bustiere type thingy.
But this? She should be nipping out all over the place. Not that that's necessarily a bad thing, but it's a fact. Unless that puppy is glued to her, it's not staying put.