Is this actually allowed?

Take a look at Prada’s brogue flatforms from their Spring 2011 collection here:
Gorgeous (of course). The price tag, not as much: According to
The Cut, they’ll set you back $795.00 US (oh, they’re also on wait-list, natch). But then take a look at
Jeffrey Campbell‘s latest addition to his fall 2011 collection:

I mean, they are pretty amazing, but intrinsically doesn’t it just seem so wrong? It’s such a blatant knock-off, that I’m not even sure how Jeffrey Campbell can get away with it? Given the number of fashion events I go to, I don’t know I would have the stomach to handle: "Wow, Lara, are those Prada?!" and then have to say sheepishly that, nope, they’re not actually… especially if I run into Susie Sheffman from
FASHION (she has the real deal).
What do you think? Would you buy the knock-off?