Well, I must say I've seen women wear more revealing/sillier things than that when they go out to the clubs. And not many of them had the well-toned body that made the outfit look good.
From the background, it looks like she is out on the town - so I actually think it works well with the setting. If I worked out as much as Jessica Simpson (but *oddly* still had an ample bosom) I would wear that shirt.