> The publishers note that other red flags include extremely low pricing. This is due to the Pirate Sellers offering books in PDF format when “legitimate distributors rarely, if ever, sell their textbooks in PDF form.” That Google allegedly helps users to refine their searches by adding ‘pdf’ via a dedicated button, only makes matters worse, they add.

Yep, instead legitimate publishers sell in some proprietary format that is only readable by special software that screams their hate at legitimate customers by a horrifying UX.