That's what I think when I see this commercial:
I was absolutely floored when I first saw this, especially the fact that it's an advertisement for a KID'S MEAL. The ad is aimed at kids. Women shaking their butts (square or otherwise) in the camera, having the burger king run his tape measure across them, setting his square on them, etc. - it's aimed at kids.
I pity the parents who have to explain this to their kids who are old enough to understand it. Also, can you think of the conversations kids are having on the playground? I'm sure some girls will get teased that they have square butts, "just like the girls on the Burger King commercial." Way to go, Burger King. Real classy.