By the time Carrie Bradshaw was shown wearing the Dior “Extremes” for the fourth time in last summer’s Sex and the City Movie, it was practically a done deal: The cutout platform sandals would be the official must-have summer shoe.

But even at the steep retail price of $780, the Extremes sold out almost instantly after the movie’s premiere. The New York Post reported that the wait list extended through most of the summer. Would the Carrie-clones be forced to spend the season without their gladiator platforms?

Hardly. In fact, the selection of well-priced alternatives was remarkable. Bakers, Steve Madden, and ASOS all produced extremely similar versions of the coveted shoe. Too similar, argued some fashion police.

Had Bakers and company crossed the line into “piracy” territory, or were they simply trying to make the summer’s hottest shoe trend available to the masses? After all, the $100 versions made no illusions about the fact that they are lower-quality imitations of the Dior original. Even Sarah Jessica Parker had essentially come out in favor of knockoff — or rather, “highly inspired” — fashion with the Foley and Corinna-style bag she designed for Bitten. And fashion blogs were full of comments along the lines of “I actually like the Madden version better!”

Welcome to an infamous “grey area” in style ethics, the fine line between inspiration and shameless imitation. It is where the bulk of high street shops live, such as Zara and Forever 21. And as the latter retailer can tell you after its string of legal battles with Diane Von Furstenberg, there is little consensus about where the boundaries lie.

But if you were to take all the mimicry out of fashion, would there be anything left? The imitation/inspiration divide presents us with what is essentially a paradox, as fashion law expert and Counterfeit Chic writer Susan Scafidi explains, “The history of fashion is a tale of innovation, but also of imitation. Trendsetters create and embrace new styles, but without copycats there would be no trends. This tension lies at the heart of Counterfeit Chic.”

So how “inspired” is too inspired? Click on any image for a slideshow exploring this classic grey area in fashion law and ethics.