I've read many complaints from sellers on Amazon where some other vendor hijacks a product page and starts selling cheap knock-offs. Buyers have no idea who's going to fulfill their order, and they might end up with a fake or defective product.

This article from The Verge describes how listings get hijacked[archived]:

• Amazon’s platform is extremely open. Multiple sellers can sell on a listing, and any of them can edit it. In theory, this leads to improved listings. In practice, black-hat sellers can alter the images and text to depict a different product, or add unrelated items as "variations."
• On a popular listing, other sellers will report the hijacker to Amazon and try to get them kicked off. (The hijacker may report them back or escalate in other ways.) But on abandoned listings, there’s no one to notice the change.
• Certain listings are restricted in terms of who can make changes. This includes Amazon’s own brands, which is why hijacking likely happens when someone asks Seller Support to implement the changes, something the team is constantly asked to do for legitimate reasons.

Last night I finished watching the show Making the Cut[archived]. It's a fashion show very similar to Project Runaway[archived], and the winners of each episode can sell one of their pieces on a special Amazon store for the show. After finishing the show I decided to check out the store out of curiosity, and I discovered that many of the listings have also been hijacked! Here's one[archived] of the many 1-star reviews[archived] for one of the products:

After ordering this sweatshirt on the night it became available after watching Making the Cut, I finally received it. It came in a plastic bag from China with no label other than an "s". It's made of the cheapest material I have ever seen and on the front butterfly it says OOTA (note: the designer is called "Jonny Cota").

How can they let this happen in their own special store?