As a maker and designer I am always aware of the people who copy. It has happened to me numerous times and mainly I ignore it, sometimes a curt email does the job, but usually it is just someone trying to do what I do and not realising that they will get spotted. When I started selling on Etsy I had someone buy a doorstop from me on ebay and immediately copy the design and sell it on Etsy. I was alerted by other uk etsy sellers who kept me up to speed with her goings on and her reaction to my emails asking her to remove them. Her shop has since closed and she won't be missed by many, especially not me!
Sadly there is currently a situation with a UK etsy designer HidenSeek who has had her beautiful and unique illustrations taken and manipulated by Paperchase. Paperchases line is that they are not the same, as theirs has a different 'feel' My personal opinion is that their behaviour stinks, Twitter has apparently gone mad over this and a Google search reveals it as a seriously hot topic with the press becoming increasingly interested.
Please please spread the word and help protect the rights of indie makers.
Read more here here and here
Latest news is that Amazon who were stocking the Paperchase item in question has today removed it from their site!