Yes, I am aware that they're playing off the name of their bra. Yes, I know that they're trying to catch your attention by using the word body. But there are so many different ways they could have gone with this ad, none of which required them to write the word bodies (which would have been correct).
Moral of the story: Don't use an apostrophe to make any words plural (with the exception of "do's and don'ts"). It instantly lowers the credibility of your blog — or, in this case, a pricey print ad.
Have you seen any advertising mishaps lately? Do plurals trip you up?